3-aryl bicyclic [4,5,0] hydroxamic acids as hdac inhibitors

ABSTRACT

The present invention relates to inhibitors of zinc-dependent histone deacetylases (HDACs) useful in the treatment of diseases or disorders associated with HDAC6, having a Formula I: 
     
       
         
         
             
             
         
       
     
     where R, L, X 1 , X 2 , X 3 , X 4 , Y 1 , Y 2 , Y 3 , and Y 4  are described herein.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority of U.S. Provisional Application No. 62/110,716, filed Feb. 2, 2015 and U.S. Provisional Application No. 62/205,438, filed Aug. 14, 2015, both of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to inhibitors of zinc-dependent histone deacetylases (HDACs) useful in the treatment of diseases or disorders associated with HDACs including cell proliferation diseases (e.g., cancer), neurological and inflammatory diseases. Specifically, this invention is concerned with compounds and compositions inhibiting HDACs, methods of treating diseases associated with HDACs, and methods of synthesizing these compounds.

BACKGROUND OF THE INVENTION

Many members of the HDAC family require zinc (Zn) to function properly. For instance, the isozyme histone deacetylase 6 (HDAC6) is a zinc-dependent histone deacetylase that possesses histone deacetylase activity. Other family members include HDACs 1-5 and 7-11. (De Ruijter et al, Biochem. J. 2003. 370; 737-749).

HDAC6 is known to deacetylate and associate with α-tubulin, cortactin, heat shock protein 90, β-catenin, glucose-regulated protein 78 kDa, myosin heavy chain 9, heat shock cognate protein 70, and dnaJ homolog subfamily A member 1 (reviewed in Li et al, FEBS J. 2013, 280: 775-93; Zhang et al, Protein Cell. 2015, 6(1): 42-54). Diseases in which HDAC6 inhibition could have a potential benefit include cancer (reviewed in Aldana-Masangkay et al, J. Biomed. Biotechnol. 2011, 875824), specifically: multiple myeloma (Hideshima et al, Proc. Natl. Acad. Sci. USA 2005, 102(24):8567-8572); lung cancer (Kamemura et al, Biochem. Biophys. Res. Commun. 2008, 374(1):84-89); ovarian cancer (Bazzaro et al, Clin. Cancer Res. 2008, 14(22):7340-7347); breast cancer (Lee et al, Cancer Res. 2008, 68(18):7561-7569; Park et al, Oncol. Rep. 2011, 25: 1677-81; Rey et al, Eur. J. Cell Biol. 2011, 90: 128-35); prostate cancer (Seidel et al, Biochem Pharmacol. 2015 (15)00714-5); pancreatic cancer (Nawrocki et al, Cancer Res. 2006, 66(7):3773-3781); renal cancer (Cha et al, Clin. Cancer Res. 2009, 15(3): 840-850); hepatocellular cancer (Ding et al, FEBS Lett. 2013, 587:880-6; Kanno et al, Oncol. Rep. 2012, 28: 867-73); lymphomas (Ding et al, Cancer Cell Int. 2014, 14:139; Amengual et al, Clin. Cancer Res. 2015, 21(20):4663-75); and leukemias such as acute myeloid leukemia (AML) (Fiskus et al, Blood 2008, 112(7):2896-2905) and acute lymphoblastic leukemia (ALL) (Rodriguez-Gonzalez et al, Blood 2008, 1 12(1 1): Abstract 1923)).

Inhibition of HDAC6 may also have a role in cardiovascular disease, including pressure overload, chronic ischemia, and infarction-reperfusion injury (Tannous et al, Circulation 2008, 1 17(24):3070-3078); bacterial infection, including those caused by uropathogenic Escherichia coli (Dhakal and Mulve, J. Biol. Chem. 2008, 284(1):446-454); neurological diseases caused by accumulation of intracellular protein aggregates such as Alzheimer's, Parkinson's and Huntington's disease (reviewed in Simoes-Pires et al, Mol. Neurodegener. 2013, 8: 7) or central nervous system trauma caused by tissue injury, oxidative-stress induced neuronal or axomal degeneration (Rivieccio et al, Proc. Natl. Acad. Sci. USA 2009, 106(46):19599-195604); and inflammation and autoimmune diseases through enhanced T cell-mediated immune tolerance at least in part through effects on regulatory T cells, including rheumatoid arthritis, psoriasis, spondylitis arthritis, psoriatic arthritis, multiple sclerosis, lupus, colitis and graft versus host disease (reviewed in Wang et al, Nat. Rev. Drug Disc. 2009 8(12):969-981; Vishwakarma et al, Int. Immunopharmacol. 2013, 16:72-8; Kalin et al, J. Med. Chem. 2012, 55:639-51); and fibrotic disease, including kidney fibrosis (Choi et al, Vascul. Pharmacol. 2015 72:130-140).

Four HDAC inhibitors are currently approved for the treatment of some cancers. These are suberanilohydroxamic acid (Vorinostat; Zolinza®) for the treatment of cutaneous T cell lymphoma and multiple myeloma; Romidepsin (FK228; FR901228; Istodax®) for the treatment of peripheral T cell lymphoma; Panobinostat (LBH-589; Farydak®) for the treatment of multiple myeloma; and belinostat (PXD101; Beleodaq®) for the treatment of peripheral T cell lymphoma. However, these drugs are of limited effectiveness and can give rise to unwanted side effects. Thus there is a need for drugs with an improved safety-efficacy profile.

Given the complex function of HDAC6 and their potential utility in the treatment of proliferative diseases, neurological diseases, and inflammatory diseases, there is a need for HDAC inhibitors (e.g., HDAC6 inhibitors) with good therapeutic properties.

SUMMARY OF THE INVENTION

One aspect of the invention relates to compounds of Formula I:

and pharmaceutically acceptable salts, prodrugs, solvates, hydrates, tautomers and isomers thereof,

wherein:

X¹ is independently CR¹R², NR³, O, or C═O;

X² and X⁴ are each independently CR¹R², C═O, S(O) or SO₂;

X³ is CR^(1′)R^(2′); wherein X⁴, X², and X¹ are not all simultaneously CR¹R²;

Y¹ and Y⁴ are not bonded to —C(O)NHOH and are each independently N or CR¹;

Y² and Y³ are each independently N or CR¹ when not bonded to —C(O)NHOH and Y² and Y³ are C when bonded to —C(O)NHOH;

L is a bond, —(CR¹R²)_(n)—, —C(O)O—, —C(O)NR³—, —S(O)₂—, —S(O)₂NR³—, —S(O)—, or —S(O)NR³—, wherein L is bound to the ring nitrogen through the carbonyl or sulfonyl group;

R is independently —H, —C₁-C₆ alkyl, —C₂-C₆ alkenyl, —C₄-C₈ cycloalkenyl, —C₂-C₆ alkynyl, —C₃-C₈ cycloalkyl, —C₅-C₁₂ spirocycle, heterocyclyl, spiroheterocyclyl, aryl, or heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O, wherein each alkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkyl, spirocycle, heterocyclyl, spiroheterocyclyl, aryl, or heteroaryl is optionally substituted with one or more —OH, halogen, oxo, —NO₂, —CN, —R¹, —R², —OR³, —NHR³, —NR³R⁴, —S(O)₂NR³R⁴, —S(O)₂R¹, —C(O)R¹, —CO₂R¹, —NR³S(O)₂R¹, —S(O)R¹, —S(O)NR³R⁴, —NR³S(O)R¹, heterocycle, aryl, or heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O;

each R¹ and R² are independently, and at each occurrence, —H, —R³, —R⁴, —C₁-C₆ alkyl, —C₂-C₆ alkenyl, —C₄-C₈ cycloalkenyl, —C₂-C₆ alkynyl, —C₃-C₈ cycloalkyl, heterocyclyl, aryl, heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O, —OH, halogen, —NO₂, —CN, —NHC₁-C₆ alkyl, —N(C₁-C₆ alkyl)₂, —S(O)₂N(C₁-C₆ alkyl)₂, —N(C₁-C₆ alkyl)S(O)₂R⁵, —S(O)₂(C₁-C₆ alkyl), —(C₁-C₆ alkyl)S(O)₂R⁵, —C(O)C₁-C₆ alkyl, —CO₂C₁-C₆ alkyl, —N(C₁-C₆ alkyl)S(O)₂C₁-C₆ alkyl, or —(CHR⁵)_(n)NR³R⁴, wherein each alkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, or heteroaryl is optionally substituted with one or more substituents selected from —OH, halogen, —NO₂, oxo, —CN, —R⁵, —OR³, —NHR³, NR³R⁴, —S(O)₂N(R³)₂—, —S(O)₂R⁵, —C(O)R⁵, —CO₂R⁵, —NR³S(O)₂R⁵, —S(O)R⁵, —S(O)NR³R⁴, —NR³S(O)R⁵, heterocycle, aryl, and heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O;

or R¹ and R² can combine with the atom to which they are both attached to form a spirocycle, spiroheterocycle, or a spirocycloalkenyl;

or R¹ and R², when on adjacent atoms, can combine to form a heterocycle, cycloalkyl, aryl, heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O, or cycloalkenyl;

or R¹ and R², when on non-adjacent atoms, can combine to form a bridging cycloalkyl, cycloalkenyl, or heterocycloalkyl;

R^(1′) and R^(2′) are independently, and at each occurrence, H, aryl, or heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O, wherein each aryl or heteroaryl is optionally substituted with one or more substituents selected from —OH, halogen, —NO₂, oxo, —CN, —R³, —R⁵, —OR³, —NHR³, —NR³R⁴, —S(O)₂N(R³)₂, —S(O)₂R⁵, —C(O)R⁵, —CO₂R⁵, —NR³S(O)₂R⁵, —S(O)R⁵, —S(O)NR³R⁴, —NR³S(O)R⁵, heterocycle, aryl, and heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O, wherein at least one of R^(1′) or R^(2′) is not H;

R³ and R⁴ are independently, and at each occurrence, —H, —C₁-C₆ alkyl, —C₂-C₆ alkenyl, —C₄-C₈ cycloalkenyl, —C₂-C₆ alkynyl, —C₃-C₈ cycloalkyl, heterocyclyl, aryl, heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O, —S(O)₂N(C₁-C₆ alkyl)₂, —S(O)₂(C₁-C₆ alkyl), —(C₁-C₆ alkyl)S(O)₂R⁵, —C(O)C₁-C₆ alkyl, —CO₂C₁-C₆ alkyl, or —(CHR⁵)_(n)N(C₁-C₆ alkyl)₂, wherein each alkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, or heteroaryl is optionally substituted with one or more substituents selected from —OH, halogen, —NO₂, oxo, —CN, —R⁵, —O(C₁-C₆) alkyl, —NH(C₁-C₆) alkyl, —N(C₁-C₆ alkyl)₂, —S(O)₂N(C₁-C₆ alkyl)₂, —S(O)₂NHC₁-C₆ alkyl, —C(O)C₁-C₆ alkyl, —CO₂C₁-C₆ alkyl, —N(C₁-C₆ alkyl)S(O)₂C₁-C₆ alkyl, —S(O)R⁵, —S(O)N(C₁-C₆ alkyl)₂, —N(C₁-C₆ alkyl)S(O)R⁵, heterocycle, aryl, and heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O;

or R³ and R can combine with the nitrogen atom to which they are attached to form a heterocycle or heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O, wherein each heterocycle or heteroaryl is optionally substituted with —R⁴, —OR⁴, or —NR⁴R⁵;

R⁵ is independently, and at each occurrence, —H, —C₁-C₆ alkyl, —C₂-C₆ alkenyl, —C₄-C₈ cycloalkenyl, —C₂-C₆ alkynyl, —C₃-C₈ cycloalkyl, heterocyclyl, aryl, heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O, —OH, halogen, —NO₂, —CN, —NHC₁-C₆ alkyl, —N(C₁-C₆ alkyl)₂, —S(O)₂NH(C₁-C₆ alkyl), —S(O)₂N(C₁-C₆ alkyl)₂, —S(O)₂C₁-C₆ alkyl, —C(O)C₁-C₆ alkyl, —CO₂C₁-C₆ alkyl, —N(C₁-C₆ alkyl)SO₂C₁-C₆ alkyl, —S(O)(C₁-C₆ alkyl), —S(O)N(C₁-C₆ alkyl)₂, —N(C₁-C₆ alkyl)S(O)(C₁-C₆ alkyl) or —(CH₂)_(n)N(C₁-C₆ alkyl)₂; and

each n is independently and at each occurrence an integer from 0 to 6; and

provided that when X² and X⁴ are both C═O, X¹ is not NR³.

Another aspect of the invention relates to a method of treating a disease or disorder associated with HDAC6 modulation in a subject in need thereof, comprising administering to the subject an effective amount of a compound of Formula I.

Another aspect of the invention is directed to a method of inhibiting HDAC6. The method involves administering to a patient in need thereof an effective amount of a compound of Formula I.

Another aspect of the disclosure relates to a compound of Formula I, or a pharmaceutically acceptable salt, prodrug, solvate, hydrate, tautomer, or isomer thereof, for use in treating or preventing a disease associated with HDAC6 modulation.

Another aspect of the disclosure relates to the use of a compound of Formula I, or a pharmaceutically acceptable salt, prodrug, solvate, hydrate, tautomer, or isomer thereof, in the manufacture of a medicament for treating or preventing a disease associated with HDAC6 modulation.

Another aspect of the invention is directed to pharmaceutical compositions comprising a compound of Formula I and a pharmaceutically acceptable carrier. The pharmaceutically acceptable carrier can further include an excipient, diluent, or surfactant. The pharmaceutical composition can be effective for treating a disease or disorder associated with HDAC6 modulation in a subject in need thereof. The pharmaceutical compositions can comprise the compounds of the present invention for use in treating diseases described herein. The compositions can contain at least one compound of the invention and a pharmaceutically acceptable carrier. The invention also provides the use of the compounds described herein in the manufacture of a medicament for the treatment of a disease associated with HDACs.

The present invention also provides methods for the treatment of human diseases or disorders including, without limitation, oncological, neurological, inflammatory, autoimmune, infectious, metabolic, hematologic, or cardiovascular diseases or disorders.

The present invention also provides compounds that are useful in inhibiting of zinc-dependent HDAC enzymes, and in particular HDAC6. These compounds can also be useful in the treatment of diseases including cancer.

The present invention further provides compounds that can inhibit HDAC6. In some embodiments, the efficacy-safety profile of the compounds of the current invention can be improved relative to other known HDAC (e.g., HDAC6) inhibitors. Additionally, the present technology also has the advantage of being able to be used for a number of different types of diseases, including cancer and non-cancer indications. Additional features and advantages of the present technology will be apparent to one of skill in the art upon reading the Detailed Description of the Invention, below.

DETAILED DESCRIPTION OF THE INVENTION

HDAC6 is a zinc-dependent histone deacetylase that has two catalytic domains. HDAC6 can interact with and deacetylate non-histone proteins, including HSP90 and α-tubulin. Acetylation of HSP90 is associated with loss of function of HSP90. HDAC6 is also implicated in the degradation of misfolded proteins as part of the aggresome. Accordingly, inhibition of HDAC6 can have downstream effects that can play a role in the development of certain diseases such as cancer. The present invention provides inhibitors of HDAC6 and methods for using the same to treat disease.

In a first aspect of the invention, compounds of the Formula I are described:

and pharmaceutically acceptable salts, prodrugs, solvates, hydrates, tautomers, and isomers thereof, wherein R, L, X¹, X², X³, X⁴, Y¹, Y², Y³, and Y⁴ are described as above.

The details of the invention are set forth in the accompanying description below. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, illustrative methods and materials are now described. Other features, objects, and advantages of the invention will be apparent from the description and from the claims. In the specification and the appended claims, the singular forms also include the plural unless the context clearly dictates otherwise. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. All patents and publications cited in this specification are incorporated herein by reference in their entireties.

DEFINITIONS

The articles “a” and “an” are used in this disclosure to refer to one or more than one (e.g., to at least one) of the grammatical object of the article. By way of example, “an element” means one element or more than one element.

The term “and/or” is used in this disclosure to mean either “and” or “or” unless indicated otherwise.

The term “optionally substituted” is understood to mean that a given chemical moiety (e.g., an alkyl group) can (but is not required to) be bonded other substituents (e.g., heteroatoms). For instance, an alkyl group that is optionally substituted can be a fully saturated alkyl chain (e.g., a pure hydrocarbon). Alternatively, the same optionally substituted alkyl group can have substituents different from hydrogen. For instance, it can, at any point along the chain be bounded to a halogen atom, a hydroxyl group, or any other substituent described herein. Thus the term “optionally substituted” means that a given chemical moiety has the potential to contain other functional groups, but does not necessarily have any further functional groups.

The term “aryl” refers to cyclic, aromatic hydrocarbon groups that have 1 to 2 aromatic rings, including monocyclic or bicyclic groups such as phenyl, biphenyl or naphthyl.

Where containing two aromatic rings (bicyclic, etc.), the aromatic rings of the aryl group may be joined at a single point (e.g., biphenyl), or fused (e.g., naphthyl). The aryl group may be optionally substituted with one or more substituents, e.g., 1 to 5 substituents, at any point of attachment. Exemplary substituents include, but are not limited to, —H, -halogen, —O—C₁-C₆ alkyl, —C₁-C₆ alkyl, —OC₂-C₆ alkenyl, —OC₂-C₆ alkynyl, —C₂-C₆ alkenyl, —C₂-C₆ alkynyl, —OH, —OP(O)(OH)₂, —OC(O)C₁-C₆ alkyl, —C(O)C₁-C₆ alkyl, —OC(O)OC₁-C₆ alkyl, —NH₂, —NH(C₁-C₆ alkyl), —N(C₁-C₆ alkyl)₂, —S(O)₂—C₁-C₆ alkyl, —S(O)NHC₁-C₆ alkyl, and —S(O)N(C₁-C₆ alkyl)₂. The substituents can themselves be optionally substituted. Furthermore when containing two fused rings the aryl groups herein defined may have an unsaturated or partially saturated ring fused with a fully saturated ring. Exemplary ring systems of these aryl groups include indanyl, indenyl, tetrahydronaphthalenyl, and tetrahydrobenzoannulenyl.

Unless otherwise specifically defined, “heteroaryl” means a monovalent monocyclic aromatic radical of 5 to 24 ring atoms or a polycyclic aromatic radical, containing one or more ring heteroatoms selected from N, S, P, and O, the remaining ring atoms being C. Heteroaryl as herein defined also means a bicyclic heteroaromatic group wherein the heteroatom is selected from N, S, P, and O. The aromatic radical is optionally substituted independently with one or more substituents described herein. Examples include, but are not limited to, furyl, thienyl, pyrrolyl, pyridyl, pyrazolyl, pyrimidinyl, imidazolyl, isoxazolyl, oxazolyl, oxadiazolyl, pyrazinyl, indolyl, thiophen-2-yl, quinolyl, benzopyranyl, isothiazolyl, thiazolyl, thiadiazole, indazole, benzimidazolyl, thieno[3,2-b]thiophene, triazolyl, triazinyl, imidazo[1,2-b]pyrazolyl, furo[2,3-c]pyridinyl, imidazo[1,2-a]pyridinyl, indazolyl, pyrrolo[2,3-c]pyridinyl, pyrrolo[3,2-c]pyridinyl, pyrazolo[3,4-c]pyridinyl, thieno[3,2-c]pyridinyl, thieno[2,3-c]pyridinyl, thieno[2,3-b]pyridinyl, benzothiazolyl, indolyl, indolinyl, indolinonyl, dihydrobenzothiophenyl, dihydrobenzofuranyl, benzofuran, chromanyl, thiochromanyl, tetrahydroquinolinyl, dihydrobenzothiazine, dihydrobenzoxanyl, quinolinyl, isoquinolinyl, 1,6-naphthyridinyl, benzo[de]isoquinolinyl, pyrido[4,3-b][1,6]naphthyridinyl, thieno[2,3-b]pyrazinyl, quinazolinyl, tetrazolo[1,5-a]pyridinyl, [1,2,4]triazolo[4,3-a]pyridinyl, isoindolyl, pyrrolo[2,3-b]pyridinyl, pyrrolo[3,4-b]pyridinyl, pyrrolo[3,2-b]pyridinyl, imidazo[5,4-b]pyridinyl, pyrrolo[1,2-a]pyrimidinyl, tetrahydro pyrrolo[1,2-a]pyrimidinyl, 3,4-dihydro-2H-1λ²-pyrrolo[2,1-b]pyrimidine, dibenzo[b,d]thiophene, pyridin-2-one, furo[3,2-c]pyridinyl, furo[2,3-c]pyridinyl, 1H-pyrido[3,4-b][1,4]thiazinyl, benzooxazolyl, benzoisoxazolyl, furo[2,3-b]pyridinyl, benzothiophenyl, 1,5-naphthyridinyl, furo[3,2-b]pyridine, [1,2,4]triazolo[1,5-a]pyridinyl, benzo[1,2,3]triazolyl, imidazo[1,2-a]pyrimidinyl, [1,2,4]triazolo[4,3-b]pyridazinyl, benzo[c][1,2,5]thiadiazolyl, benzo[c][1,2,5]oxadiazole, 1,3-dihydro-2H-benzo[d]imidazol-2-one, 3,4-dihydro-2H-pyrazolo[1,5-b][1,2]oxazinyl, 4,5,6,7-tetrahydropyrazolo[1,5-a]pyridinyl, thiazolo[5,4-d]thiazolyl, imidazo[2,1-b][1,3,4]thiadiazolyl, thieno[2,3-b]pyrrolyl, 3H-indolyl, and derivatives thereof. Furthermore when containing two fused rings the heteroaryl groups herein defined may have an unsaturated or partially saturated ring fused with a fully saturated ring. Exemplary ring systems of these heteroaryl groups include indolinyl, indolinonyl, dihydrobenzothiophenyl, dihydrobenzofuran, chromanyl, thiochromanyl, tetrahydroquinolinyl, dihydrobenzothiazine, 3,4-dihydro-1H-isoquinolinyl, 2,3-dihydrobenzofuran, indolinyl, indolyl, and dihydrobenzoxanyl.

“Alkyl” refers to a straight or branched chain saturated hydrocarbon. C₁-C₆ alkyl groups contain 1 to 6 carbon atoms. Examples of a C₁-C₆ alkyl group include, but are not limited to, methyl, ethyl, propyl, butyl, pentyl, isopropyl, isobutyl, sec-butyl and tert-butyl, isopentyl and neopentyl.

The term “alkenyl” means an aliphatic hydrocarbon group containing a carbon-carbon double bond and which may be straight or branched having about 2 to about 6 carbon atoms in the chain. Alkenyl groups can have 2 to about 4 carbon atoms in the chain. Branched means that one or more lower alkyl groups such as methyl, ethyl, or propyl are attached to a linear alkenyl chain. Exemplary alkenyl groups include ethenyl, propenyl, n-butenyl, and i-butenyl. A C₂-C₆ alkenyl group is an alkenyl group containing between 2 and 6 carbon atoms.

The term “alkynyl” means an aliphatic hydrocarbon group containing a carbon-carbon triple bond and which may be straight or branched having about 2 to about 6 carbon atoms in the chain. Alkynyl groups can have 2 to about 4 carbon atoms in the chain. Branched means that one or more lower alkyl groups such as methyl, ethyl, or propyl are attached to a linear alkynyl chain. Exemplary alkynyl groups include ethynyl, propynyl, n-butynyl, 2-butynyl, 3-methylbutynyl, and n-pentynyl. A C₂-C₆ alkynyl group is an alkynyl group containing between 2 and 6 carbon atoms.

The term “cycloalkyl” means monocyclic or polycyclic saturated carbon rings containing 3-18 carbon atoms. Examples of cycloalkyl groups include, without limitations, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptanyl, cyclooctanyl, norboranyl, norborenyl, bicyclo[2.2.2]octanyl, or bicyclo[2.2.2]octenyl. A C₃-C₈ cycloalkyl is a cycloalkyl group containing between 3 and 8 carbon atoms. A cycloalkyl group can be fused (e.g., decalin) or bridged (e.g., norbornane).

The term “cycloalkenyl” means monocyclic, non-aromatic unsaturated carbon rings containing 3-18 carbon atoms. Examples of cycloalkenyl groups include, without limitation, cyclopentenyl, cyclohexenyl, cycloheptenyl, cyclooctenyl, and norborenyl. A C₃-C₈ cycloalkenyl is a cycloalkenyl group containing between 3 and 8 carbon atoms.

The terms “heterocyclyl” or “heterocycloalkyl” or “heterocycle” refer to monocyclic or polycyclic 3 to 24-membered rings containing carbon and heteroatoms taken from oxygen, nitrogen, or sulfur and wherein there is not delocalized nt electrons (aromaticity) shared among the ring carbon or heteroatoms. Heterocyclyl rings include, but are not limited to, oxetanyl, azetadinyl, tetrahydrofuranyl, pyrrolidinyl, oxazolinyl, oxazolidinyl, thiazolinyl, thiazolidinyl, pyranyl, thiopyranyl, tetrahydropyranyl, dioxalinyl, piperidinyl, morpholinyl, thiomorpholinyl, thiomorpholinyl S-oxide, thiomorpholinyl S-dioxide, piperazinyl, azepinyl, oxepinyl, diazepinyl, tropanyl, and homotropanyl. A heterocyclyl or heterocycloalkyl ring can also be fused or bridged, e.g., can be a bicyclic ring.

As used herein, the term “halo” or “halogen” means fluoro, chloro, bromo, or iodo.

The term “carbonyl” refers to a functional group composing a carbon atom double-bonded to an oxygen atom. It can be abbreviated herein as “oxo”, as C(O), or as C═O.

“Spirocycle” or “spirocyclic” means carbogenic bicyclic ring systems with both rings connected through a single atom. The ring can be different in size and nature, or identical in size and nature. Examples include spiropentane, spirohexane, spiroheptane, spirooctane, spirononane, or spirodecane. One or both of the rings in a spirocycle can be fused to another ring carbocyclic, heterocyclic, aromatic, or heteroaromatic ring. One or more of the carbon atoms in the spirocycle can be substituted with a heteroatom (e.g., O, N, S, or P). A C₃-C₁₂ spirocycle is a spirocycle containing between 3 and 12 carbon atoms. One or more of the carbon atoms can be substituted with a heteroatom.

The term “spirocyclic heterocycle” or “spiroheterocycle” is understood to mean a spirocycle wherein at least one of the rings is a heterocycle (e.g., at least one of the rings is furanyl, morpholinyl, or piperadinyl).

The disclosure also includes pharmaceutical compositions comprising an effective amount of a disclosed compound and a pharmaceutically acceptable carrier. Representative “pharmaceutically acceptable salts” include, e.g., water-soluble and water-insoluble salts, such as the acetate, amsonate (4,4-diaminostilbene-2,2-disulfonate), benzenesulfonate, benzonate, bicarbonate, bisulfate, bitartrate, borate, bromide, butyrate, calcium, calcium edetate, camsylate, carbonate, chloride, citrate, clavulariate, dihydrochloride, edetate, edisylate, estolate, esylate, fumarate, gluceptate, gluconate, glutamate, glycollylarsanilate, hexafluorophosphate, hexylresorcinate, hydrabamine, hydrobromide, hydrochloride, hydroxynaphthoate, iodide, isethionate, lactate, lactobionate, laurate, magnesium, malate, maleate, mandelate, mesylate, methyl bromide, methyl nitrate, methyl sulfate, mucate, napsylate, nitrate, N-methylglucamine ammonium salt, 3-hydroxy-2-naphthoate, oleate, oxalate, palmitate, pamoate (1,1-methene-bis-2-hydroxy-3-naphthoate, einbonate), pantothenate, phosphate/diphosphate, picrate, polygalacturonate, propionate, p-toluenesulfonate, salicylate, stearate, subacetate, succinate, sulfate, sulfosalicylate, suramate, tannate, tartrate, decollate, tosylate, triethiodide, and valerate salts.

The term “stereoisomers” refers to the set of compounds which have the same number and type of atoms and share the same bond connectivity between those atoms, but differ in three dimensional structure. The term “stereoisomer” refers to any member of this set of compounds.

The term “diastereomers” refers to the set of stereoisomers which cannot be made superimposable by rotation around single bonds. For example, cis- and trans-double bonds, endo- and exo-substitution on bicyclic ring systems, and compounds containing multiple stereogenic centers with different relative configurations are considered to be diastereomers. The term “diastereomer” refers to any member of this set of compounds. In some examples presented, the synthetic route may produce a single diastereomer or a mixture of diastereomers. In some cases these diastereomers were separated and in other cases a wavy bond is used to indicate the structural element where configuration is variable.

The term “enantiomers” refers to a pair of stereoisomers which are non-superimposable mirror images of one another. The term “enantiomer” refers to a single member of this pair of stereoisomers. The term “racemic” refers to a 1:1 mixture of a pair of enantiomers.

The term “tautomers” refers to a set of compounds that have the same number and type of atoms, but differ in bond connectivity and are in equilibrium with one another. A “tautomer” is a single member of this set of compounds. Typically a single tautomer is drawn but it is understood that this single structure is meant to represent all possible tautomers that might exist. Examples include enol-ketone tautomerism. When a ketone is drawn it is understood that both the enol and ketone forms are part of the invention.

An “effective amount” when used in connection with a compound is an amount effective for treating or preventing a disease in a subject as described herein.

The term “carrier”, as used in this disclosure, encompasses carriers, excipients, and diluents and means a material, composition or vehicle, such as a liquid or solid filler, diluent, excipient, solvent or encapsulating material, involved in carrying or transporting a pharmaceutical agent from one organ, or portion of the body, to another organ, or portion of the body of a subject.

The term “treating” with regard to a subject, refers to improving at least one symptom of the subject's disorder. Treating includes curing, improving, or at least partially ameliorating the disorder.

The term “disorder” is used in this disclosure to mean, and is used interchangeably with, the terms disease, condition, or illness, unless otherwise indicated.

The term “administer”, “administering”, or “administration” as used in this disclosure refers to either directly administering a disclosed compound or pharmaceutically acceptable salt of the disclosed compound or a composition to a subject, or administering a prodrug derivative or analog of the compound or pharmaceutically acceptable salt of the compound or composition to the subject, which can form an equivalent amount of active compound within the subject's body.

The term “prodrug,” as used in this disclosure, means a compound which is convertible in vivo by metabolic means (e.g., by hydrolysis) to a disclosed compound. Furthermore, as used herein a prodrug is a drug which is inactive in the body, but is transformed in the body typically either during absorption or after absorption from the gastrointestinal tract into the active compound. The conversion of the prodrug into the active compound in the body may be done chemically or biologically (e.g., using an enzyme).

The term “solvate” refers to a complex of variable stoichiometry formed by a solute and solvent. Such solvents for the purpose of the invention may not interfere with the biological activity of the solute. Examples of suitable solvents include, but are not limited to, water, MeOH, EtOH, and AcOH. Solvates wherein water is the solvent molecule are typically referred to as hydrates. Hydrates include compositions containing stoichiometric amounts of water, as well as compositions containing variable amounts of water.

The term “isomer” refers to compounds that have the same composition and molecular weight but differ in physical and/or chemical properties. The structural difference may be in constitution (geometric isomers) or in the ability to rotate the plane of polarized light (stereoisomers). With regard to stereoisomers, the compounds of Formula I may have one or more asymmetric carbon atom and may occur as racemates, racemic mixtures and as individual enantiomers or diastereomers.

A “patient” or “subject” is a mammal, e.g., a human, mouse, rat, guinea pig, dog, cat, horse, cow, pig, or non-human primate, such as a monkey, chimpanzee, baboon or rhesus.

In another embodiment of the invention are described compounds of the Formula IA:

and pharmaceutically acceptable salts, prodrugs, solvates, hydrates, tautomers or isomer thereof; where R, L, X¹, X², X³, X⁴, Y¹, Y³, and Y⁴ are defined as above in Formula I.

In another embodiment of the compounds of Formula IA, X⁴ is CR¹R².

In another embodiment of the compounds of Formula IA, X¹ is NR³, O, or C═O.

In another embodiment of the compounds of Formula IA, X¹ is O.

In another embodiment of the compounds of Formula IA, X¹ is O and X⁴ is CR¹R².

In some embodiments of the invention, the compounds of Formula IA may be of the Formula IA-1:

For instance, in some embodiments of Formula IA-1, the compounds can be of the Formula IA-1a, Formula IA-1b, or Formula IA-1c:

In other embodiments of the compounds of Formula IA, the compound is of the Formula IA-2:

In yet other another embodiments of the compounds of Formula IA, the compound is of the Formula IA-3:

In yet other embodiments of the compounds of Formula IA, the compound is of the Formula IA-4:

In yet other another embodiments of the compounds of Formula IA, the compound is of the Formula IA-5:

In yet other another embodiments of the compounds of Formula IA, the compound is of the Formula IA-6:

In yet other another embodiments of the compounds of Formula IA, the compound is of the Formula IA-7:

In other embodiments of the compounds of Formula IA, the compound is of the Formula IA-8:

In a further embodiment of the compounds of Formula IA, the compound is also of the Formula IA-9:

In another embodiment of the compounds of Formula IA, the compound is of the Formula IA-10:

In another embodiment of the compounds of Formula IA, the compound is of the Formula IA-11:

In one embodiment of the invention are also disclosed compounds of the Formula IB:

and pharmaceutically acceptable salts, prodrugs, solvates, hydrates, enantiomers and isomers thereof where R, L, X¹, X², X³, X⁴, Y¹, Y², and Y⁴ are defined as above in Formula I.

In one embodiment of the compounds of Formula IB, X⁴ is CR¹R².

In another embodiment of the compounds of Formula IB, X¹ is NR³, O, or C═O.

In another embodiment of the compounds of Formula IB, X¹ is O.

In another embodiment of the compounds of Formula IB, X¹ is O and X⁴ is CR¹R².

In another embodiment of the compounds of Formula IB, X¹ is N, X² is C═O, and X⁴ is CR¹R².

In some embodiments of the invention, the compounds of Formula IB, may be of the Formula IB-1:

In yet other embodiments of the compounds of Formula IB, the compound is of the Formula (IB-2):

In other embodiments of the compounds of Formula IB, the compound may also be of the Formula IB-3:

In other embodiments of the compounds of Formula IB, the compound is of the Formula (IB-4):

In a further embodiment of the compounds of Formula IB, the compound is also of the Formula IB-5:

In some embodiments of Formula (I), X¹ is O. In another embodiment, X¹ is O and X² is CR¹R². In yet another embodiment, X¹ is O, X² is CR¹R², and X³ is CR^(1′)R^(2′). In another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), and X⁴ is CR¹R². In yet another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), X⁴ is CR¹R², and Y¹ is CR¹. In another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), X⁴ is CR¹R², Y¹ is CR¹, and Y³ is CR¹. In yet another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), X⁴ is CR¹R², Y¹ is CR¹, Y³ is CR¹, and Y⁴ is CR¹. In another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², X⁴ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, and Y² is C. In yet another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), X⁴ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, and L is —C(O)—. In another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), X⁴ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, L is —C(O)—, and R^(1′) is H. In yet another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), X⁴ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, L is —C(O)—, R^(1′) is H, and R^(2′)is aryl or heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O, wherein the aryl or heteroaryl is optionally substituted with one or more substituents selected from halogen or —R³.

In some embodiments of Formula (I), X¹ is O. In another embodiment, X¹ is O and X² is CR¹R². In yet another embodiment, X¹ is O, X² is CR¹R², and X³ is CR^(1′)R^(2′). In another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), and X⁴ is CR¹R². In yet another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), X⁴ is CR¹R², and Y¹ is CR¹. In another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), X⁴ is CR¹R², Y¹ is CR¹, and Y³ is CR¹. In yet another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), X⁴ is CR¹R², Y¹ is CR¹, Y³ is CR¹, and Y⁴ is CR¹. In another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², X⁴ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, and Y² is C. In yet another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), X⁴ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, and L is a bond. In another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), X⁴ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, L is a bond, and R^(1′) is H. In yet another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), X⁴ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, L is a bond, R^(1′) is H, and R^(2′)is aryl or heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O, wherein the aryl or heteroaryl is optionally substituted with one or more substituents selected from halogen or —R³.

In some embodiments of Formula (I), X¹ is O. In another embodiment, X¹ is O and X² is CR¹R². In yet another embodiment, X¹ is O, X² is CR¹R², and X³ is CR^(1′)R^(2′). In another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), and X⁴ is CR¹R². In yet another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), X⁴ is CR¹R², and Y¹ is CR¹. In another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′,) X⁴ is CR¹R², Y¹ is CR¹, and Y³ is CR¹. In yet another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), X⁴ is CR¹R², Y¹ is CR¹, Y³ is CR¹, and Y⁴ is CR¹. In another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), X⁴ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, and Y² is C. In yet another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), X⁴ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, and L is —(CR¹R²)_(n)—. In another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), X⁴ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, L is —(CR¹R²)_(n)—, and n is 1. In another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), X⁴ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, L is —(CR¹R²)_(n)—, n is 1, and R^(1′) is H. In yet another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), X⁴ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, L is —(CR¹R²)_(n)—, n is 1, R^(1′) is H, and R^(2′)is aryl or heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O, wherein the aryl or heteroaryl is optionally substituted with one or more substituents selected from halogen or —R³.

In some embodiments of Formula (I), X¹ is O. In another embodiment, X¹ is O and X² is CR¹R². In yet another embodiment, X¹ is O, X² is CR¹R², and X³ is CR^(1′)R^(2′). In another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), and X⁴ is CR¹R². In yet another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), X⁴ is CR¹R², and Y¹ is CR¹. In another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), X⁴ is CR¹R², Y¹ is CR¹, and Y³ is CR¹. In yet another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), X⁴ is CR¹R², Y¹ is CR¹, Y³ is CR¹, and Y⁴ is CR¹. In another embodiment, X¹ is O, X² is CR¹R², X³ is CR¹R², X⁴ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, and Y² is C. In yet another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), X⁴ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, and L is —C(O)NR³—. In another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), X⁴ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, L is —C(O)NR³—, and R^(1′) is H. In yet another embodiment, X¹ is O, X² is CR¹R², X³ is CR^(1′)R^(2′), X⁴ is CR¹R², Y¹ is CR¹, Y³ is CR¹, Y⁴ is CR¹, Y² is C, L is —C(O)NR³—, R^(1′) is H, and R^(2′)is aryl or heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O, wherein the aryl or heteroaryl is optionally substituted with one or more substituents selected from halogen or —R³.

In some embodiments of Formula (I), R is —C₁-C₆ alkyl, —C₄-C₈ cycloalkenyl, —C₃-C₈ cycloalkyl, —C₅-C₁₂ spirocycle, heterocyclyl, spiroheterocyclyl, aryl, or heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O, wherein each alkyl, cycloalkenyl, cycloalkyl, spirocycle, heterocyclyl, spiroheterocyclyl, aryl, or heteroaryl is optionally substituted with one or more —OH, halogen, oxo, —NO₂, —CN, —R¹, —R², —OR³, —NHR³, —NR³R⁴, —S(O)₂NR³R⁴, —S(O)₂R¹, —C(O)R¹, or —CO₂R¹, —NR³S(O)₂R¹, —S(O)R¹, —S(O)NR³R⁴, —NR³S(O)R¹, heterocycle, aryl, or heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O.

In some embodiments of Formula (I), R¹ and R² combine with the atom to which they are both attached to form a spirocycle. In another embodiment, R¹ and R² combine with the atom to which they are both attached to form a spiroheterocycle. In another embodiment, R¹ and R² combine with the atom to which they are both attached to form a spirocycloalkenyl.

In some embodiments of Formula (I), R¹ and R², when on adjacent atoms, combine to form a heterocycle. In another embodiment, R¹ and R², when on adjacent atoms, combine to form a cycloalkyl. In yet another embodiment, R¹ and R², when on adjacent atoms, combine to form a cycloalkenyl. In another embodiment, R¹ and R², when on adjacent atoms, combine to form an aryl. In yet another embodiment, R¹ and R², when on adjacent atoms, combine to form a heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O.

In some embodiments of Formula (I), R¹ and R², when on non-adjacent atoms, combine to form a bridging cycloalkyl. In another embodiment, R¹ and R², when on non-adjacent atoms, combine to form a bridging cycloalkenyl. In yet another embodiment, R¹ and R², when on non-adjacent atoms, combine to form a heterocycloalkyl.

In some embodiments of Formula (I), R³ and R combine with the nitrogen atom to which they are attached to form a heterocycle optionally substituted with —R⁴, —OR⁴, or —NR⁴R⁵. In some embodiments of Formula (I), R³ and R combine with the nitrogen atom to which they are attached to form a heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O, optionally substituted with —R⁴, —OR⁴, or —NR⁴R⁵.

In some embodiments of Formula (I), n is 1 to 6. In another embodiment, n is 0 to 5. In yet another embodiment, n is 0 to 4. In yet another embodiment, n is 1 to 4. In another embodiment, n is 0 to 3. In yet another embodiment, n is 0 to 2. In yet another embodiment, n is 0 or 1. In another embodiment, n is 1 or 2.

In some embodiments of Formula (I), X⁴, X², and X¹ are not all simultaneously CR¹R².

In some embodiments of Formula (I), X¹ is O, X² is CR¹R², and X⁴ is CR¹R². In another embodiment, X² is C═O, X⁴ is C═O, and X¹ is CR¹R². In yet another embodiment, X¹ is NR³, X² is C═O, and X⁴ is CR¹R².

Non-limiting illustrative compounds of the disclosure include:

-   (S)—N-hydroxy-4-methyl-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (R)—N-hydroxy-4-methyl-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (S)—N-hydroxy-4-(4-methoxybenzyl)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (R)—N-hydroxy-4-(4-methoxybenzyl)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (S)—N-hydroxy-3,4-diphenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (R)—N-hydroxy-3,4-diphenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (S)—N-hydroxy-4-(4-methoxypiperidine-1-carbonyl)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (S)—N-hydroxy-4-(4-methylpiperazine-1-carbonyl)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (S)-4-(4-acetylpiperazine-1-carbonyl)-N-hydroxy-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (S)—N-hydroxy-3-phenyl-4-(piperidine-1-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (S)—N-hydroxy-3-phenyl-4-(pyrrolidine-1-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (S)—N4-cyclohexyl-N8-hydroxy-3-phenyl-2,3-dihydrobenzo[f][1,4]oxazepine-4,8(5H)-dicarboxamide; -   (S)—N8-hydroxy-3-phenyl-N4-(tetrahydro-2H-pyran-4-yl)-2,3-dihydrobenzo[f][1,4]oxazepine-4,8(5H)-dicarboxamide; -   (S)—N8-hydroxy-N4,3-diphenyl-2,3-dihydrobenzo[f][1,4]oxazepine-4,8(5H)-dicarboxamide; -   (S)—N8-hydroxy-3-phenyl-N4-(pyridin-4-yl)-2,3-dihydrobenzo[f][1,4]oxazepine-4,8(5H)-dicarboxamide; -   (S)—N8-hydroxy-3-phenyl-N4-(pyridin-3-yl)-2,3-dihydrobenzo[f][1,4]oxazepine-4,8(5H)-dicarboxamide; -   (S)—N-hydroxy-4-(morpholine-4-carbonyl)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (S)—N8-hydroxy-N4,N4-dimethyl-3-phenyl-2,3-dihydrobenzo[f][1,4]oxazepine-4,8(5H)-dicarboxamide; -   (S)-4-((4-fluorophenyl)sulfonyl)-N-hydroxy-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (S)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(4-(trifluoromethyl)phenyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (S)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(p-tolyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (S)-3-(4-chlorophenyl)-N-hydroxy-4-(morpholine-4-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (S)-3-(3-chlorophenyl)-N-hydroxy-4-(morpholine-4-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (S)-3-(4-fluorophenyl)-N-hydroxy-4-(morpholine-4-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (R)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(pyridin-3-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (S)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(pyridin-3-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide;

In another embodiment, non-limiting illustrative compounds of the disclosure include:

-   (S)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(o-tolyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (S)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(3-(trifluoromethyl)phenyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (R)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(3-(trifluoromethyl)phenyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (S)-3-(3-fluorophenyl)-N-hydroxy-4-(morpholine-4-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide -   (R)-3-(3-fluorophenyl)-N-hydroxy-4-(morpholine-4-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide -   (S)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(2-(trifluoromethyl)phenyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide -   (R)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(2-(trifluoromethyl)phenyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (S)-3-(2-fluorophenyl)-N-hydroxy-4-(morpholine-4-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (R)-3-(2-fluorophenyl)-N-hydroxy-4-(morpholine-4-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide -   (S)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(quinoxalin-6-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (S)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(quinolin-6-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide -   (S)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(quinolin-7-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (S)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(naphthalen-2-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (R)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(quinoxalin-6-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (R)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(quinolin-6-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (R)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(quinolin-7-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (R)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(naphthalen-2-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (R)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(quinoxalin-5-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (R)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(quinolin-5-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (R)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(quinolin-8-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (R)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(naphthalen-1-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; -   (3S)—N-hydroxy-5-methyl-4-(morpholine-4-carbonyl)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide;     and -   (S)-6-fluoro-N-hydroxy-4-(morpholine-4-carbonyl)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide.

In another embodiment of the invention, the compounds of Formula I are enantiomers. In some embodiments the compounds are the (S)-enantiomer. In other embodiments the compounds are the (R)-enantiomer. In yet other embodiments, the compounds of Formula I may be (+) or (−) enantiomers.

It should be understood that all isomeric forms are included within the present invention, including mixtures thereof. If the compound contains a double bond, the substituent may be in the E or Z configuration. If the compound contains a disubstituted cycloalkyl, the cycloalkyl substituent may have a cis- or trans configuration. All tautomeric forms are also intended to be included.

Methods of Synthesizing the Disclosed Compounds

The compounds of the present invention may be made by a variety of methods, including standard chemistry. Suitable synthetic routes are depicted in the schemes given below.

The compounds of Formula I may be prepared by methods known in the art of organic synthesis as set forth in part by the following synthetic schemes and examples. In the schemes described below, it is well understood that protecting groups for sensitive or reactive groups are employed where necessary in accordance with general principles or chemistry. Protecting groups are manipulated according to standard methods of organic synthesis (T. W. Greene and P. G. M. Wuts, “Protective Groups in Organic Synthesis”, Third edition, Wiley, New York 1999). These groups are removed at a convenient stage of the compound synthesis using methods that are readily apparent to those skilled in the art. The selection processes, as well as the reaction conditions and order of their execution, shall be consistent with the preparation of compounds of Formula I.

Those skilled in the art will recognize if a stereocenter exists in the compounds of Formula I. Accordingly, the present invention includes both possible stereoisomers (unless specified in the synthesis) and includes not only racemic compounds but the individual enantiomers and/or diastereomers as well. When a compound is desired as a single enantiomer or diastereomer, it may be obtained by stereospecific synthesis or by resolution of the final product or any convenient intermediate. Resolution of the final product, an intermediate, or a starting material may be affected by any suitable method known in the art. See, for example, “Stereochemistry of Organic Compounds” by E. L. Eliel, S. H. Wilen, and L. N. Mander (Wiley-Interscience, 1994).

The compounds described herein may be made from commercially available starting materials or synthesized using known organic, inorganic, and/or enzymatic processes.

Preparation of Compounds

The compounds of the present invention can be prepared in a number of ways well known to those skilled in the art of organic synthesis. By way of example, compounds of the present invention can be synthesized using the methods described below, together with synthetic methods known in the art of synthetic organic chemistry, or variations thereon as appreciated by those skilled in the art. These methods include, but are not limited, to those methods described below. Compounds of the present disclosure can be synthesized by following the steps outlined in General Schemes 1, 2, 3, 4, and 5 which comprise different sequences of assembling intermediates 2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h, 2i, 2j, 2k, 2m, 2n, 2o, 2p, 2q, 2r, 2s, 2t, 2u, 2v, 2w, 2x, 2y, 2z, 2aa, 2bb, and 2cc. Starting materials are either commercially available or made by known procedures in the reported literature or as illustrated.

wherein L, R, R¹, R², R^(1′), R^(2′), Y¹ and Y² are defined as in Formula (I).

The general way of preparing target molecules of Formula (I) by using intermediates 2a, 2b, 2c, 2d, and 2e is outlined in General Scheme 1. Nucleophilic addition of alcohol 2b to Intermediate 2a using a base, e.g., potassium carbonate (K₂CO₃), in a solvent, e.g., acetonitrile (MeCN), provides Intermediate 2c. Cyclization of Intermediate 2c in the presence of a catalytic amount of a metal catalyst, e.g., copper iodide (CuI), palladium acetate (Pd(OAc)₂), etc., and a base, e.g., potassium carbonate (K₂CO₃), in a solvent, e.g., isopropanol (i-PrOH), optionally at elevated temperature provides Intermediate 2d. Addition of the R-L moiety can be achieved via alkylation, reductive amination, arylation, urea formation, or sulfonation. For example, alkylation of Intermediate 2d with an alkyl halide in the presence of a base, e.g., sodium hydride (NaH), and optionally at elevated temperatures provides Intermediate 2e. Treatment of Intermediate 2e with hydroxylamine and a base, e.g., aqueous sodium hydroxide (aq. NaOH) in a solvent, e.g., tetrahydrofuran (THF) and/or methanol (MeOH), provides compounds of Formula (I).

wherein L, R, R^(1′), and R^(2′) are defined as in Formula (I).

The general way of preparing target molecules of Formula (I) by using intermediates 2f, 2g, 2h, 2i, 2j, and 2k is outlined in General Scheme 2. Nucleophilic addition of amine 2g to Intermediate 2f using a base, e.g., N,N-diisopropylethylamine (DIEA), and in a solvent, e.g., MeCN, dichloromethane (DCM), or DMF, provides Intermediate 2h. Protection of the amine group in intermediate 2h with a typical acid labile protecting group (e.g., t-butoxycarbonyl (Boc)) using an alkyl chloride and 4-Dimethylaminopyridine (DMAP), in a solvent e.g., DCM or tetrahydrofuran (THF), followed by hydrogenation in the presence of a metal catalyst, e.g., palladium on carbon, and hydrogen (H₂) gas in a solvent, e.g., DCM, provides Intermediate 2i. Cyclization of Intermediate 2i in the presence of a base, e.g., potassium carbonate (K₂CO₃), and in a solvent, e.g., isopropanol (i-PrOH), optionally at elevated temperatures provides Intermediate 2j. Addition of the R-L moiety can be achieved via alkylation, reductive amination, arylation, urea formation, or sulfonation. For example, alkylation of Intermediate 2j with an alkyl halide in the presence of a base, e.g., sodium hydride (NaH), and optionally at elevated temperatures provides Intermediate 2k. Treatment of Intermediate 2k with hydroxylamine and a base, e.g., aqueous sodium hydroxide (aq. NaOH) in a solvent, e.g., tetrahydrofuran (THF) and/or methanol (MeOH), provides compounds of Formula (I).

wherein L, R, R^(1′), and R^(2′) are defined as in Formula (I).

The general way of preparing target molecules of Formula (I) by using intermediates 2m, 2n, 2o, 2p, and 2q, is outlined in General Scheme 3. Sulfonylation of alcohol 2n with Intermediate 2m in the presence of a metal oxide, e.g., MgO, and in a solvent, e.g., THF and or water (H₂O), provides Intermediate 2o. Cyclization of Intermediate 2o in the presence of a base, e.g., sodium methoxide (NaOMe), and in a solvent, e.g., methanol (MeOH), i-PrOH, etc., provides Intermediate 2p. Addition of the R-L moiety can be achieved via alkylation, reductive amination, arylation, urea formation, or sulfonation. For example, alkylation of Intermediate 2p with an alkyl halide in the presence of a base, e.g., sodium hydride (NaH), and optionally at elevated temperatures provides Intermediate 2q. Treatment of Intermediate 2q with hydroxylamine and a base, e.g., aqueous sodium hydroxide (aq. NaOH), in a solvent, e.g., tetrahydrofuran (THF) and/or methanol (MeOH), provides compounds of Formula (I).

wherein L, R, R^(1′), and R^(2′) are defined as in Formula (I).

The general way of preparing target molecules of Formula (I) by using intermediates 2r, 2s, 2t, 2u, and 2v, is outlined in General Scheme 4. Intermediate 2t can be obtained by alkylation of 2s with phenol 2r using a Mitsunobu reagent (e.g., diethyl azodicarboxylate (DEAD) or diisopropyl azodicarboxylate (DIAD)), and triphenyl phosphine in a solvent, e.g., tetrahydrofuran (THF), dichloromethane (DCM). Deprotection of intermediate 2t using a strong acid such as trifluoroacetic acid (TFA) in a solvent, e.g., dichloromethane (DCM), followed by cyclization in the presence of a base, e.g., triethylamine (Et₃N), and optionally in a solvent, e.g., THF, MeOH, etc., at elevated temperature provides Intermediate 2u. Addition of the R-L moiety can be achieved via alkylation, reductive amination, arylation, urea formation, or sulfonation. For example, alkylation of Intermediate 2u with an alkyl halide in the presence of a base, e.g., sodium hydride (NaH), and optionally at elevated temperatures provides Intermediate 2v. Treatment of Intermediate 2v with hydroxylamine and a base, e.g., aqueous sodium hydroxide (aq. NaOH) in a solvent, e.g., tetrahydrofuran (THF) and/or methanol (MeOH), provides compounds of Formula (I).

wherein L, R, R^(1′), and R^(2′) are defined as in Formula (I).

The general way of preparing target molecules of Formula (I) by using intermediates 2w, 2x, 2y, 2z, 2aa, 2bb, and 2cc, is outlined in General Scheme 5. Alkylation of phenol 2w with Intermediate 2x using potassium iodide (KI) and a base, e.g., potassium carbonate (K₂CO₃), in a solvent, e.g., MeCN, THF, etc., provides Intermediate 2y. Deprotection of Intermediate 2y using a strong acid such as trifluoroacetic acid (TFA) in a solvent, e.g., dichloromethane (DCM) followed by cyclization via intramolecular reductive amination in the presence of sodium borohydride or sodium cyanoborohydride in a solvent, e.g., THF, MeOH, etc., provides Intermediate 2z. Protection of the amine group in intermediate 2z with a typical acid labile protecting group (e.g., t-butoxycarbonyl (Boc)) using an alkyl chloride and optionally 4-DMAP in a solvent e.g., DCM or tetrahydrofuran (THF), followed by carbonylation in the presence of a metal catalyst, e.g., [1,1′-Bis(diphenylphosphino)ferrocene]palladium(II) dichloride, and carbon monoxide (CO) gas in a solvent, e.g., DCM, provides Intermediate 2aa. Deprotection of intermediate 2aa using a strong acid such as trifluoroacetic acid (TFA) in a solvent, e.g., dichloromethane (DCM) provides Intermediate 2bb. Addition of the R-L moiety can be achieved via alkylation, reductive amination, arylation, urea formation, or sulfonation. For example, alkylation of Intermediate 2bb with an alkyl halide in the presence of a base, e.g., sodium hydride (NaH), and optionally at elevated temperatures provides Intermediate 2cc. Treatment of Intermediate 2cc with hydroxylamine and a base, e.g., aqueous sodium hydroxide (aq. NaOH), in a solvent, e.g., tetrahydrofuran (THF) and/or methanol (MeOH), provides compounds of Formula (I).

Methods of Using the Disclosed Compounds

Another aspect of the invention relates to a method of treating a disease associated with HDAC, e.g., HDAC6, modulation in a subject in need thereof. The method involves administering to a patient in need of treatment for diseases or disorders associated with HDAC, e.g., HDAC6, modulation an effective amount of a compound of Formula I. In an embodiment, the disease can be, but is not limited to, cancer, neurodegenerative disease, neurodevelopmental disease, inflammatory or autoimmune disease, infection, metabolic disease, hematologic disease, or cardiovascular disease.

Another aspect of the invention is directed to a method of inhibiting an HDAC, e.g., HDAC6. The method involves administering to a patient in need thereof an effective amount of Formula I.

The present invention relates to compositions capable of modulating the activity of (e.g., inhibiting) HDACs, for instance HDAC6. The present invention also relates to the therapeutic use of such compounds.

One therapeutic use of the compounds of the present invention is to treat proliferative diseases or disorders such as cancer. Cancer can be understood as abnormal or unregulated cell growth within a patient and can include, but is not limited to lung cancer, ovarian cancer, breast cancer, prostate cancer, pancreatic cancer, hepatocellular cancer, renal cancer and leukemias such as acute myeloid leukemia and acute lymphoblastic leukemia. Additional cancer types include T-cell lymphoma (e.g., cutaneous T-cell lymphoma, peripheral T-cell lymphoma), and multiple myeloma.

One therapeutic use of the compounds of the present invention is to treat neurological diseases or disorders or neurodegeneration. Neurological disorders are understood as disorders of the nervous system (e.g., the brain and spinal cord). Neurological disorders or neurodegenerative diseases can include, but are not limited to epilepsy, attention deficit disorder (ADD), Alzheimer's disease, Parkinson's Disease, Huntington's Disease, amyotrophic lateral sclerosis, spinal muscular atrophy, essential tremor, central nervous system trauma caused by tissue injury, oxidative stress-induced neuronal or axomal degeneration, and multiple sclerosis.

Another therapeutic use of the compounds of the present invention is to treat neurodevelopmental disorders. Neurodevelopmental disorders can include, but are not limited to, Rett syndrome.

Another therapeutic use of the compounds of the present invention is also to treat inflammatory diseases or disorders. Inflammation can be understood as a host's response to an initial injury or infection. Symptoms of inflammation can include, but are not limited to redness, swelling, pain, heat and loss of function. Inflammation may be caused by the upregulation of pro-inflammatory cytokines such as IL-1β, and increased expression of the FOXP3 transcription factor.

Another therapeutic use of the compounds of the present invention is also to treat autoimmune diseases or disorders. Autoimmune disorders are understood as disorders wherein a host's own immune system responds to tissues and substances occurring naturally in the host's body. Autoimmune diseases can include, but are not limited to Rheumatoid arthritis, spondylitis arthritis, psoriatic arthritis, multiple sclerosis, systemic lupus erythematosus, inflammatory bowel disease, graft versus host disease, transplant rejection, fibrotic disease, Crohn's Disease, type-1 diabetes, Eczema, and psoriasis.

Another therapeutic use of the compounds of the present invention is also to treat infectious diseases or disorders. Infections or infectious diseases are caused by the invasion of a foreign pathogen. The infection may be caused by, for instance, a bacteria, a fungus, or virus. For example, a bacterial infection may be caused by a E. coli.

Yet another therapeutic use of the compounds of the present invention is also to treat metabolic diseases or disorders. Metabolic diseases can be characterized as abnormalities in the way that a subject stores energy. Metabolic disorders can include, but are not limited to metabolic syndrome, diabetes, obesity, high blood pressure, and heart failure.

Yet another therapeutic use of the compounds of the present invention is also to treat hematologic disorders. Hematologic diseases primarily affect the blood. Hematologic disorders can include, but are not limited to anemia, lymphoma, and leukemia.

Yet another therapeutic use of the compounds of the present invention is also to treat cardiovascular diseases or disorders. Cardiovascular diseases affect the heart and blood vessels of a patient. Exemplary conditions include but are not limited to cardiovascular stress, pressure overload, chronic ischemia, infarction-reperfusion injury, hypertension, atherosclerosis, peripheral artery disease, and heart failure.

Another aspect of the present disclosure relates to a compound of Formula (I), or a pharmaceutically acceptable salt, hydrate, solvate, prodrug, stereoisomer, or tautomer thereof, for use in treating or preventing a disease associated with HDAC6 modulation. In some embodiments, the disease is cancer, neurodegenerative disease, neurodevelopmental disorder, inflammatory or autoimmune disease, infection, metabolic disease, hematologic disease, or cardiovascular disease. In some embodiments, the compound inhibits a histone deacetylase. In another embodiment, the compound inhibits a zinc-dependent histone deacetylase. In another embodiment, the compound inhibits the HDAC6 isozyme zinc-dependent histone deacetylase.

In another aspect, the present disclosure relates to the use of a compound of Formula (I), or a pharmaceutically acceptable salt, hydrate, solvate, prodrug, stereoisomer, or tautomer thereof, in the manufacture of a medicament for treating or preventing a disease associated with HDAC6 modulation. In some embodiments, the disease is cancer, neurodegenerative disease, neurodevelopmental disorder, inflammatory or autoimmune disease, infection, metabolic disease, hematologic disease, or cardiovascular disease. In some embodiments, the compound inhibits a histone deacetylase. In another embodiment, the compound inhibits a zinc-dependent histone deacetylase. In another embodiment, the compound inhibits the HDAC6 isozyme zinc-dependent histone deacetylase.

In some embodiments, the cancer is cutaneous T-cell lymphoma, peripheral T-cell lymphoma, multiple myeloma, leukemia, lung, ovarian, breast, prostate, pancreatic, hepatocellular or renal cancer. In other embodiments, the neurodegenerative disease is Alzheimer's, Huntington's, Parkinson's, Amyotrophic Lateral Sclerosis, or spinal muscular atrophy. In other embodiments, the neurodevelopmental disorder is Rett syndrome. In yet other embodiments, the inflammatory or autoimmune disease is rheumatoid arthritis, spondylitis arthritis, psoriatic arthritis, psoriasis, multiple sclerosis, systemic lupus erythematosus, inflammatory bowel diseases, graft versus host disease, transplant rejection or fibrotic disease.

The disclosed compound can be administered in effective amounts to treat or prevent a disorder and/or prevent the development thereof in subjects.

Administration of the disclosed compounds can be accomplished via any mode of administration for therapeutic agents. These modes include systemic or local administration such as oral, nasal, parenteral, transdermal, subcutaneous, vaginal, buccal, rectal or topical administration modes.

Depending on the intended mode of administration, the disclosed compositions can be in solid, semi-solid or liquid dosage form, such as, for example, injectables, tablets, suppositories, pills, time-release capsules, elixirs, tinctures, emulsions, syrups, powders, liquids, suspensions, or the like, sometimes in unit dosages and consistent with conventional pharmaceutical practices. Likewise, they can also be administered in intravenous (both bolus and infusion), intraperitoneal, subcutaneous or intramuscular form, all using forms well known to those skilled in the pharmaceutical arts.

Illustrative pharmaceutical compositions are tablets and gelatin capsules comprising a Compound of the Invention and a pharmaceutically acceptable carrier, such as a) a diluent, e.g., purified water, triglyceride oils, such as hydrogenated or partially hydrogenated vegetable oil, or mixtures thereof, corn oil, olive oil, sunflower oil, safflower oil, fish oils, such as EPA or DHA, or their esters or triglycerides or mixtures thereof, omega-3 fatty acids or derivatives thereof, lactose, dextrose, sucrose, mannitol, sorbitol, cellulose, sodium, saccharin, glucose and/or glycine; b) a lubricant, e.g., silica, talcum, stearic acid, its magnesium or calcium salt, sodium oleate, sodium stearate, magnesium stearate, sodium benzoate, sodium acetate, sodium chloride and/or polyethylene glycol; for tablets also; c) a binder, e.g., magnesium aluminum silicate, starch paste, gelatin, tragacanth, methylcellulose, sodium carboxymethylcellulose, magnesium carbonate, natural sugars such as glucose or beta-lactose, corn sweeteners, natural and synthetic gums such as acacia, tragacanth or sodium alginate, waxes and/or polyvinylpyrrolidone, if desired; d) a disintegrant, e.g., starches, agar, methyl cellulose, bentonite, xanthan gum, alginic acid or its sodium salt, or effervescent mixtures; e) absorbent, colorant, flavorant and sweetener; f) an emulsifier or dispersing agent, such as Tween 80, Labrasol, HPMC, DOSS, caproyl 909, labrafac, labrafil, peceol, transcutol, capmul MCM, capmul PG-12, captex 355, gelucire, vitamin E TGPS or other acceptable emulsifier; and/or g) an agent that enhances absorption of the compound such as cyclodextrin, hydroxypropyl-cyclodextrin, PEG400, PEG200.

Liquid, particularly injectable, compositions can, for example, be prepared by dissolution, dispersion, etc. For example, the disclosed compound is dissolved in or mixed with a pharmaceutically acceptable solvent such as, for example, water, saline, aqueous dextrose, glycerol, ethanol, and the like, to thereby form an injectable isotonic solution or suspension. Proteins such as albumin, chylomicron particles, or serum proteins can be used to solubilize the disclosed compounds.

The disclosed compounds can be also formulated as a suppository that can be prepared from fatty emulsions or suspensions; using polyalkylene glycols such as propylene glycol, as the carrier.

The disclosed compounds can also be administered in the form of liposome delivery systems, such as small unilamellar vesicles, large unilamellar vesicles and multilamellar vesicles. Liposomes can be formed from a variety of phospholipids, containing cholesterol, stearylamine or phosphatidylcholines. In some embodiments, a film of lipid components is hydrated with an aqueous solution of drug to a form lipid layer encapsulating the drug, as described in U.S. Pat. No. 5,262,564.

Disclosed compounds can also be delivered by the use of monoclonal antibodies as individual carriers to which the disclosed compounds are coupled. The disclosed compounds can also be coupled with soluble polymers as targetable drug carriers. Such polymers can include, polyvinylpyrrolidone, pyran copolymer, polyhydroxypropylmethacrylamidephenol, polyhydroxyethylaspanami dephenol, or polyethyleneoxidepolylysine substituted with palmitoyl residues. Furthermore, the disclosed compounds can be coupled to a class of biodegradable polymers useful in achieving controlled release of a drug, for example, polylactic acid, polyepsilon caprolactone, polyhydroxy butyric acid, polyorthoesters, polyacetals, polydihydropyrans, polycyanoacrylates and cross-linked or amphipathic block copolymers of hydrogels. In one embodiment, disclosed compounds are not covalently bound to a polymer, e.g., a polycarboxylic acid polymer, or a polyacrylate.

Parental injectable administration is generally used for subcutaneous, intramuscular or intravenous injections and infusions. Injectables can be prepared in conventional forms, either as liquid solutions or suspensions or solid forms suitable for dissolving in liquid prior to injection.

Another aspect of the invention relates to a pharmaceutical composition comprising a compound of Formula I and a pharmaceutically acceptable carrier. The pharmaceutically acceptable carrier can further include an excipient, diluent, or surfactant.

Compositions can be prepared according to conventional mixing, granulating or coating methods, respectively, and the present pharmaceutical compositions can contain from about 0.1% to about 99%, from about 5% to about 90%, or from about 1% to about 20% of the disclosed compound by weight or volume.

The dosage regimen utilizing the disclosed compound is selected in accordance with a variety of factors including type, species, age, weight, sex and medical condition of the patient; the severity of the condition to be treated; the route of administration; the renal or hepatic function of the patient; and the particular disclosed compound employed. A physician or veterinarian of ordinary skill in the art can readily determine and prescribe the effective amount of the drug required to prevent, counter or arrest the progress of the condition.

Effective dosage amounts of the disclosed compounds, when used for the indicated effects, range from about 0.5 mg to about 5000 mg of the disclosed compound as needed to treat the condition. Compositions for in vivo or in vitro use can contain about 0.5, 5, 20, 50, 75, 100, 150, 250, 500, 750, 1000, 1250, 2500, 3500, or 5000 mg of the disclosed compound, or, in a range of from one amount to another amount in the list of doses. In one embodiment, the compositions are in the form of a tablet that can be scored.

Without wishing to be bound by any particular theory, the compounds of the present invention can inhibit HDACs such as HDAC6 by interacting with the zinc (Zn²⁺) ion in the protein's active site via the hydroxamic acid group bound to the aromatic ring of the compound. The binding can prevent the zinc ion from interacting with its natural substrates, thus inhibiting the enzyme.

EXAMPLES

The disclosure is further illustrated by the following examples and synthesis examples, which are not to be construed as limiting this disclosure in scope or spirit to the specific procedures herein described. It is to be understood that the examples are provided to illustrate certain embodiments and that no limitation to the scope of the disclosure is intended thereby. It is to be further understood that resort may be had to various other embodiments, modifications, and equivalents thereof which may suggest themselves to those skilled in the art without departing from the spirit of the present disclosure and/or scope of the appended claims.

The present invention includes a number of unique features and advantages compared with other inhibitors of HDAC enzymes, in particular HDAC6. For instance, the present invention features a unique class of small molecule therapeutic agents of Formula I. The compounds were designed by using crystal structure information of HDAC ligand-protein complexes as well as advanced computational chemistry tools. These techniques led to the development of new chemical scaffolds that were iteratively refined to optimize key recognition features between the ligand and receptor known to be necessary for potency.

Definitions used in the following examples and elsewhere herein are:

-   aq.: aqueous     Boc t-butoxycarbonyl     CDCl₃: deuterated chloroform     CH₂Cl₂: methylene chloride, dichloromethane     Cu(OAc)₂ copper (II) acetate     CuI: copper (I) iodide     DMSO: dimethylsulfoxide     Et₃N: triethylamine     EtOAc: ethyl acetate     h: hours     H₂O: water     HCl: hydrochloric acid     K₂CO₃: potassium carbonate     MeCN: acetonitrile     MeOH: methanol     MgSO₄: magnesium sulfate     min: minutes     NaBH(OAc)₃ sodium triacetoxyborohydride     Na₂SO₄: sodium sulfate     NaOH: sodium hydroxide     NH₂OH: hydroxylamine     NH₄HCO₃: ammonium bicarbonate     NH₄OH ammonium hydroxide     pet. ether: petroleum ether     prep-HPLC: preparatory high pressure liquid chromatography     TFA: trifluoroacetic acid     THF: tetrahydrofuran

Example 1 Preparation of (S)—N-hydroxy-4-methyl-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide

Step-1: Methyl (S)-3-bromo-4-(((2-hydroxy-1-phenylethyl)amino)methyl)benzoate

(S)-2-Amino-2-phenylethan-1-ol (7.5 g, 54.67 mmol, 2 equiv) and K₂CO₃ (5.68 g, 40.8 mmol, 1.5 equiv) in MeCN (120 mL) were added to a 500-mL round-bottom flask. This was followed by the dropwise addition of a solution of methyl 3-bromo-4-(bromomethyl)benzoate (14 g, 45.46 mmol, 1 equiv) in MeCN (130 mL) with stirring at 0° C. The resulting mixture was stirred overnight at room temperature. The solids were removed by filtration, and the filtrate was concentrated under vacuum. The residue was purified by silica gel chromatography (EtOAc/pet. ether, 1:1) to afford the title compound as a yellow oil (9 g, 54% yield). MS: (ES, m/z): 364 [M+H]⁺.

Step-2: Methyl (S)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate

A solution of methyl (S)-3-bromo-4-(((2-hydroxy-1-phenylethyl)amino)methyl) benzoate (5 g, 13.73 mmol, 1 equiv) in isopropanol (120 mL) was added to a 150-mL sealed tube purged and maintained with an inert atmosphere of nitrogen. This was followed by the addition of K₂CO₃ (2.85 g, 20.47 mmol, 1.5 equiv) and CuI (0.78 g, 4.12 mmol, 0.3 equiv). The resulting mixture was stirred overnight at 110° C. in an oil bath. The reaction was cooled to room temperature and then concentrated under vacuum. The residue was diluted with water (200 mL) and extracted with EtOAc (2×100 mL). The combined organic layers were washed with a 30% NH₄OH solution (100 mL) and brine (200 mL), dried over anhydrous Na₂SO₄, filtered, and concentrated under vacuum. The residue was purified by silica gel chromatography (EtOAc/pet. ether, 1:3 to 1:1) to afford the title compound as a yellow solid (1.4 g, 36% yield). MS: (ES, m/z): 284 [M+H]⁺.

Step-3: Methyl (S)-4-methyl-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate

Methyl (S)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate (150 mg, 0.53 mmol, 1 equiv), acetic acid (4.5 mL), and acetal (116 mg, 2.65 mmol, 5 equiv) were added to a 25-mL round-bottom flask. The resulting mixture was stirred for 2 h at room temperature and NaBH(OAc)₃ (900 mg, 4.24 mmol, 8 equiv) was then added. The resulting mixture was stirred overnight at room temperature and then concentrated under vacuum. The residue was purified by silica gel chromatography (EtOAc/pet. ether, 1:1) to afford the title compound as a colorless oil (100 mg, 63% yield). MS: (ES, m/z): 298 [M+H]⁺.

Step-4: (S)—N-Hydroxy-4-methyl-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide

Methyl (S)-4-methyl-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate (100 mg, 0.34 mmol, 1 equiv), THF/MeOH (4:1, 1.25 mL), NH₂OH (50% in water, 2218 mg, 34 mmol, 100 equiv), and aq. 1N NaOH (0.67 mL, 2 equiv) were added to a 25-mL round-bottom flask and the resulting solution was stirred for 3 h at room temperature. The crude product was purified by Prep-HPLC (Column: XBridge C18, 5 μm, 19×150 mm; Mobile Phase A: Water/0.1% formic acid; Mobile Phase B: MeCN; Detector: UV 254, 220 nm) to afford the title compound as a white solid (47.3 mg, 42% yield). ¹H-NMR (400 MHz, DMSO-d₆) δ (ppm): 11.80-11.37 (m, 2H), 9.27-9.02 (m, 1H), 7.65-7.38 (m, 8H), 4.96-4.28 (m, 5H), 2.69 (s, 2H), 2.33 (s, 1H). MS: (ES, m/z): 299 [M+H]⁺.

TABLE 1 The following compounds were prepared according to the method of Example 1, using (R)-2-amino-2-phenylethan-1-ol or (S)-2-amino-2-phenylethan-1-ol in Step 1 where appropriate. Found Structure M + H ¹H-NMR (300 MHz, DMSO-d₆) δ (ppm)

(ES, m/z): 299 [M + H]⁺ 11.78-11.31 (m, 2H), 9.21 (br s, 1H), 7.72- 7.38 (m, 8H), 5.03-4.93 (m, 1H), 4.86-4.63 (m, 2H), 4.53-4.49 (m, 1H), 4.34-4.27 (m, 1H), 2.69 (s, 2H), 2.36 (s, 1H)

(ES, m/z): 405 [M + H]⁺ 11.37-11.00 (m, 2H), 7.72-6.92 (m, 12H), 4.98 (s, 1H), 4.63-4.36 (m, 3H), 4.26 (m, 2H), 3.87-3.36 (m, 4H)

(ES, m/z): 405 [M + H]⁺ 11.48-11.10 (m, 2H), 7.71-6.89 (m, 12H), 4.97-4.00 (m, 6H), 3.86-3.33 (m, 4H)

Example 2 Preparation of (S)—N-hydroxy-3,4-diphenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide

Step-1: Methyl (S)-3,4-diphenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate

Methyl (S)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate (100 mg, 0.35 mmol, 1 equiv), CH₂Cl₂ (5 mL), phenylboronic acid (129 mg, 1.06 mmol, 3 equiv), and 4 Å molecular sieves (35.3 mg, 100 mg/mmol) were added to a 25-mL round-bottom flask and the resulting mixture was stirred for 5 min at room temperature. Cu(OAc)₂ (64 mg, 0.35 mmol, 1 equiv) and Et₃N (107.1 mg, 1.06 mmol, 3 equiv) were then added and oxygen gas was introduced into the reaction. The resulting mixture was stirred for an additional 2 days at room temperature and then concentrated under vacuum. The residue was purified by silica gel chromatography (EtOAc/pet. ether, 1:10) to afford the title compound as a colorless oil (35.2 mg, 28% yield). MS: (ES, m/z): 360 [M+H]⁺.

Step-2: (S)—N-Hydroxy-3,4-diphenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide

Methyl (S)-3,4-diphenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate (35.2 mg, 0.10 mmol, 1 equiv), THF/MeOH (4:1, 1.25 mL), NH₂OH (50% in water, 1574 mg, 10 mmol, 100 equiv), and aq. 1N NaOH (0.38 mL, 4 equiv) were added to a 25-mL round-bottom flask and the resulting solution was stirred for 4 h at room temperature. The crude product was purified by prep-HPLC (Column: XBridge C18, 5 μm, 19×150 mm; Mobile Phase A: Water/0.1% formic acid; Mobile Phase B: MeCN; Detector: UV 254, 220 nm) to afford the title compound as a yellow solid (3 mg, 8% yield). ¹H-NMR (400 MHz, DMSO-d₆) δ (ppm): 11.22-11.09 (m, 1H), 7.60-7.34 (m, 7H), 7.17 (s, 1H), 7.08-7.04 (m, 2H), 6.60-6.56 (m, 3H), 5.30-5.20 (m, 2H), 4.81-4.59 (m, 3H). MS: (ES, m/z): 361 [M+H]⁺.

TABLE 2 The following compounds was prepared according to the method of Example 2, using (R)-2-amino-2-phenylethan-1-ol or (S)-2-amino-2-phenylethan-1-ol in Step 1. Found Structure M + H ¹H-NMR (400 MHz, DMSO-d₆) δ (ppm)

(ES, m/z): 361 [M + H]⁺ 11.15 (br s, 1H), 7.54-7.31 (m, 7H), 7.16- 7.13 (m, 1H), 7.08-6.55 (m, 5H), 5.29-5.20 (m, 2H), 4.81-4.67 (m, 3H)

Example 3 Preparation of (S)—N-hydroxy-4-(4-methoxypiperidine-1-carbonyl)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide

Step-1: Methyl (S)-4-(4-methoxypiperidine-1-carbonyl)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate

Methyl (S)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate (50 mg, 0.18 mmol, 1 equiv), THF (8 mL), triphosgene (17 mg, 0.07 mmol, 0.33 equiv), and Et₃N (36 mg, 0.36 mmol, 2 equiv) were added to a 25-mL round-bottom flask and the resulting mixture was stirred for 30 min at room temperature. This was followed by the dropwise addition of a solution of 4-methoxypiperidine (22 mg, 0.19 mmol, 1.1 equiv) in THF (2 mL) with stirring and the resulting solution was stirred for 30 min at room temperature. The reaction mixture was then poured into 20 mL of water and extracted with CH₂Cl₂ (2×50 mL). The combined organic layers were dried over anhydrous Na₂SO₄, filtered, and concentrated under vacuum to afford the title compound as a brown oil (60 mg, 80% yield). MS: (ES, m/z): 425 [M+H]⁺.

Step-2: (S)—N-Hydroxy-4-(4-methoxypiperidine-1-carbonyl)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide

Methyl (S)-4-(4-methoxypiperidine-1-carbonyl)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate (60 mg, 0.14 mmol, 1 equiv) and THF/MeOH (4:1, 2 mL) were added to a 25-mL round-bottom flask. This was followed by the dropwise addition of a solution of aq. 1N NaOH (11 mg, 0.28 mmol, 2 equiv) dissolved in the NH₂OH (50% in water, 560 mg, 8.49 mmol, 60 equiv) with stirring at 0° C. and the resulting solution was stirred for 3 h at room temperature. The solids were then removed by filtration and the crude product was purified by prep-HPLC (Column: XBridge C18 OBD, 5 μm, 19×250 mm; Mobile Phase A: Water/0.1% formic acid; Mobile Phase B: MeCN; Gradient: hold at 30% B for 8 min; Detector: UV 254, 220 nm) to afford the title compound as an off-white solid (31.9 mg, 27% yield). ¹H-NMR (400 MHz, DMSO-d₆) δ (ppm): 11.15 (br s, 1H), 9.02 (br s, 1H), 7.42-7.20 (m, 8H), 5.22-5.18 (m, 1H), 4.72-4.57 (m, 3H), 4.41-4.36 (m, 1H), 3.28-3.19 (m, 6H), 2.79-2.71 (m, 2H), 1.78-1.66 (m, 2H), 1.37-1.28 (m, 2H). MS: (ES, m/z): 426 [M+H]⁺.

TABLE 3 The following compounds were prepared according to the method Example 3. Found Structure M + H ¹H-NMR (400 MHz, DMSO-d₆) δ (ppm)

(ES, m/z): 411 [M + H]⁺ 11.20 (br s, 1H), 10.92 (m, 1H), 7.43-7.23 (m, 7H), 7.22 (s, 1H), 5.32-5.29 (m, 1H), 4.78 (d, J = 16.4 Hz, 1H), 4.66 (d, J = 16.8 Hz, 1H), 4.60-4.56 (m, 1H), 4.50-4.45 (m, 1H), 3.51-3.38 (m, 2H), 3.31-3.15 (m, 2H), 3.12-2.93 (m, 4H), 2.71 (s, 3H)

(ES, m/z): 439 [M + H]⁺ 11.11 (br s, 1H), 9.04 (br s, 1H), 7.43-7.36 (m, 4H), 7.34-7.28 (m, 3H), 7.21 (s, 1H), 5.29-5.28 (m, 1H), 4.78-4.65 (m, 2H), 4.62-4.58 (m, 1H), 4.45-4.40 (m, 1H), 3.44-3.37 (m, 2H), 3.34-3.29 (m, 2H), 3.00-2.93 (m, 4H), 1.95 (s, 3H)

(ES, m/z): 396 [M + H]⁺ 11.13 (br s, 1H), 9.03 (br s, 1H), 7.40-7.39 (m, 4H), 7.34-7.26 (m, 3H), 7.20-7.19 (m, 1H), 5.20-5.17 (m, 1H), 4.71-4.58 (m, 3H), 4.41-4.35 (m, 1H), 2.96-2.95 (m, 4H), 1.46-1.35 (m, 6H)

(ES, m/z): 382 [M + H]⁺ 7.22-7.47 (m, 8H), 5.44-5.40 (m, 1H), 4.84-4.83 (m, 2H), 4.79-4.64 (m, 1H), 4.45-4.39 (m, 1H), 3.35 (s, 1H), 3.30-3.26 (m, 1H), 3.20-3.15 (m, 2H), 1.83-1.80 (m, 4H)

(ES, m/z): 410 [M + H]⁺ 11.16 (br s, 1H), 9.03 (br s, 1H), 7.41-7.28 (m, 7H), 7.21 (s, 1H), 5.99 (d, J = 8.0 Hz, 1H), 5.69-5.67 (m, 1H), 4.94-4.90 (m, 1H), 4.66-4.50 (m, 3H), 1.71-1.61 (m, 2H), 1.51-1.43 (m, 3H), 1.19-1.04 (m, 5H)

(ES, m/z): 412 [M + H]⁺ 11.21 (br s, 1H), 9.02 (br s, 1H), 7.41-7.22 (m, 8H), 6.17 (d, J = 7.6 Hz, 1H), 5.70- 5.67 (m, 1H), 4.93 (d, J = 16.8 Hz, 1H), 4.67-4.51 (m, 3H), 3.78-3.55 (m, 3H), 3.28-3.18 (m, 2H), 1.67-1.64 (m, 1H), 1.44-1.39 (m, 2H), 1.29-1.25 (m, 1H)

(ES, m/z): 404 [M + H]⁺ 8.44 (s, 1H), 7.44-7.30 (m, 9H), 7.25 (s, 1H), 7.24-7.17 (m, 2H), 6.94-6.90 (m, 1H), 5.91-5.87 (m, 1H), 5.14 (d, J = 17.2 Hz, 1H), 4.80-4.61 (m, 3H)

(ES, m/z): 405 [M + H]⁺ 11.16 (br s, 1H), 9.04-9.02 (m, 1H), 8.92 (s, 1H), 8.23 (d, J = 6.4 Hz, 2H), 7.45-7.40 (m, 6H), 7.34-7.31 (m, 3H), 7.24 (s, 1H), 5.91-5.88 (m, 1H), 5.17-5.13 (m, 1H), 4.81-4.65 (m, 3H)

(ES, m/z): 405 [M + H]⁺ 11.07 (s, 1H), 9.03 (s, 1H), 8.71 (s, 1H), 8.56 (d, J = 2.4 Hz, 1H), 8.14 (d, J = 1.2 Hz, 1H), 7.82 (d, J = 0.8 Hz, 1H), 7.45- 7.29 (m, 7H), 7.28-7.20 (m, 2H), 5.89-5.86 (m, 1H), 5.13 (d, J = 17.2 Hz, 1H), 4.85- 4.62 (m, 3H)

Example 4 Preparation of (S)—N-hydroxy-4-(morpholine-4-carbonyl)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide

Step-1: Methyl (S)-4-(morpholine-4-carbonyl)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate

A solution of methyl (S)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate (100 mg, 0.35 mmol, 1 equiv) in CH₂Cl₂ (6 mL) was added to a 40-mL vial followed by addition of morpholine-4-carbonyl chloride (80 mg, 0.53 mmol, 1.5 equiv), Et₃N (140 mg, 1.38 mmol, 4 equiv), and 4-dimethylaminopyridine (403 mg, 3.30 mmol, 0.1 equiv) at room temperature. The resulting solution was stirred for 8 h at 50° C. The reaction mixture was diluted with CH₂Cl₂ (30 mL) and was washed with brine (3×20 mL). The combined organic layers were dried over anhydrous Na₂SO₄, filtered, and concentrated under vacuum to afford the title compound as a white solid (70 mg, 50% yield). MS: (ES, m/z): 397 [M+H]⁺.

Step-2: (S)—N-Hydroxy-4-(morpholine-4-carbonyl)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide

A solution of methyl (S)-4-(morpholine-4-carbonyl)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate (70 mg, 0.18 mmol, 1 equiv) in THF/MeOH (4:1, 2 mL) was added to an 8-mL vial followed by the addition of aq. 1N NaOH (0.4 mL, 2 equiv), and NH₂OH (50% in water, 1.6 mL, 120 equiv). The resulting solution was stirred for 1 h at room temperature and the crude product was purified by prep-HPLC (Column: XBridge C18 OBD, 5 μm, 19×250 mm; Mobile Phase A: Water/0.1% formic acid; Mobile Phase B: MeCN; Gradient: 5% B to 49% B in 8 min; Flow rate: 20 mL/min; Detector: UV 254, 220 nm) to afford the title compound as light yellow solid (42.8 mg, 61% yield). ¹H-NMR (300 MHz, DMSO-d₆) δ (ppm): 11.12 (s, 1H), 9.01 (s, 1H), 7.12-7.41 (m, 8H), 5.23-5.27 (m, 1H), 4.56-4.73 (m, 4H), 4.37-4.42 (m, 4H), 3.31-3.55 (s, 4H). MS: (ES, m/z): 398 [M+H]⁺.

Example 5 Preparation of (S)—N8-hydroxy-N4,N4-dimethyl-3-phenyl-2,3-dihydrobenzo[f][1,4]oxazepine-4,8(5H)-dicarboxamide

A 2-mL reaction vial was charged with methyl (S)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate (0.2M in 1,2-dichloroethane, 200 μL, 40 μmol) and Et₃N (neat, 11 μL, 80 μmol). Dimethylcarbamic chloride (0.2M in 1,2-dichloroethane, 400 μL, 80 μmol) was then added and the vial was sealed and shaken at room temperature overnight. The reaction mixture was diluted with brine (500 μL) and extracted with EtOAc (2×500 μL). The combined organic layers were evaporated to dryness under reduced pressure. THF/MeOH (3:1, 180 μL) was added to the vial of methyl (S)-4-(dimethylcarbamoyl)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate and it was shaken at 50° C. for 15 min to dissolve the residue. NH₂OH (50% in water, 125 μL) was added followed by aq. 1N NaOH (85 μL) and the vial was sealed and shaken at room temperature overnight. The solvent was evaporated under reduced pressure and the residue was dissolved in DMSO (500 μL) and purified by HPLC to afford the title compound (6.9 mg, 48.5% yield). MS: (ES, m/z): 356 [M+H]⁺.

Example 6 Preparation of (S)-4-((4-fluorophenyl)sulfonyl)-N-hydroxy-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide

Methyl (S)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate (0.2 M in 1,2-dichloroethane, 150 μL, 30 μmol) and Et₃N (neat, 10 μL, 71 μmol) were added to a 2-mL reaction vial followed by 4-Fluorobenzenesulfonyl chloride (0.2 M in 1,2-dichloroethane, 195 μL, 39 μmol). The vial was then sealed and shaken at room temperature overnight. The reaction mixture was diluted with brine (500 μL) and extracted with EtOAc (2×500 μL). The combined organic layers were evaporated to dryness under reduced pressure. THF/MeOH (3:1, 180 μL) was added to the vial containing methyl 4-((4-fluorophenyl)sulfonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate and it was shaken at 50° C. for 15 min to dissolve the residue. NH₂OH (50% in water, 125 μL) was then added followed by aq. 1N NaOH (85 μL) and the vial was sealed and shaken at room temperature overnight. The solvent was evaporated under reduced pressure and the residue was dissolved in DMSO (500 μL) then purified by HPLC to afford the title compound. MS: (ES, m/z): 443 [M+H]⁺.

Example 7 Preparation of (S)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(4-(trifluoromethyl)phenyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide

Step-1: Methyl (S)-3-bromo-4-(((2-hydroxy-1-(4-(trifluoromethyl)phenyl)ethyl) amino)methyl)benzoate

A solution of (S)-2-amino-2-(4-(trifluoromethyl)phenyl)ethan-1-ol (670 mg, 3.27 mmol, 1 equiv) in MeCN (60 mL) was added to a 250-mL round-bottom flask followed by the portionwise addition of K₂CO₃ (2.25 g, 16.28 mmol, 5 equiv). To this mixture was added a solution of methyl 3-bromo-4-(bromomethyl)benzoate (1000 mg, 3.25 mmol, 1 equiv) in MeCN (20 mL) dropwise with stirring and the resulting solution was stirred overnight at 50° C. in an oil bath. The reaction mixture was then cooled to room temperature and concentrated under vacuum. The resulting residue was dissolved in water (50 mL) and extracted with EtOAc (2×80 mL). The combined organic layers were dried over anhydrous Na₂SO₄, filtered, and concentrated under vacuum. The residue was purified by silica gel chromatography (EtOAc/pet. ether, 1:1) to afford the title compound as an orange oil (1.04 g, 74% yield). MS: (ES, m/z): 432 [M+H]⁺.

Step-2: Methyl (S)-3-(4-(trifluoromethyl)phenyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate

A solution of methyl (S)-3-bromo-4-(((2-hydroxy-1-(4-(trifluoromethyl)phenyl)ethyl) amino)methyl)benzoate (1.04 g, 2.41 mmol, 1 equiv) in isopropanol (18 mL) was added to a 20-mL sealed tube followed by the portionwise addition of CuI (230 mg, 1.21 mmol, 0.5 equiv). To this mixture was added K₂CO₃ (500 mg, 3.62 mmol, 1.5 equiv), in portions and the resulting solution was stirred overnight at 105° C. in an oil bath. The reaction mixture was then cooled to room temperature and the solids were removed by filtration. The filtrate was concentrated under vacuum. The resulting residue was dissolved in EtOAc (60 mL) and washed with brine (3×30 mL). The organic layer was dried over anhydrous Na₂SO₄, filtered, and concentrated under vacuum. The residue was purified by silica gel chromatography (EtOAc/pet. ether, 1:1) to afford the title compound as a green solid (560 mg, 43% yield). MS: (ES, m/z): 352 [M+H]⁺.

Step-3: Methyl (S)-4-(morpholine-4-carbonyl)-3-(4-(trifluoromethyl)phenyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate

A solution of methyl (S)-3-(4-(trifluoromethyl)phenyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate (80 mg, 0.23 mmol, 1 equiv) in CH₂Cl₂ (3 mL) and Et₃N (92 mg, 0.91 mmol, 4 equiv) were added to an 8-mL vial followed by the portionwise addition of triphosgene (33.6 mg, 0.11 mmol, 0.5 equiv) at 0° C. The resulting mixture was stirred for 30 min at room temperature and morpholine (40 mg, 0.46 mmol, 2.02 equiv) was then added dropwise with stirring. The resulting solution was stirred for 3 h at room temperature. The reaction mixture was concentrated under vacuum and the resulting residue was purified by silica gel chromatography (EtOAc/pet. ether, 1:1) to afford the title compound as a light yellow oil (90 mg, 55% yield). MS: (ES, m/z): 465 [M+H]⁺.

Step-4: (S)—N-Hydroxy-4-(morpholine-4-carbonyl)-3-(4-(trifluoromethyl)phenyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide

A solution of methyl (S)-4-(morpholine-4-carbonyl)-3-(4-(trifluoromethyl)phenyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate (90.0 mg, 0.19 mmol, 1 equiv) in THF/MeOH (4:1, 2.5 mL) was added to an 8-mL vial followed by the dropwise addition of aq. 1N NaOH (0.38 mL, 2 equiv) with stirring. To this mixture was added NH₂OH (50% in water, 767 mg, 11.63 mmol, 60 equiv) dropwise with stirring and the resulting solution was stirred for 3 h at room temperature. The crude product was purified by prep-HPLC (Column: Xbridge C18 OBD, 5 μm, 19×150 mm; Mobile Phase A: Water/0.1% formic acid; Mobile Phase B: MeCN; Gradient: 5% B to 55% B in 7 min; Detector: UV 254, 220 nm) to afford the title compound as a white solid (30.9 mg, 34% yield). ¹H-NMR (400 MHz, DMSO-d₆) δ (ppm): 11.14 (br s, 1H), 9.05 (br, 1H), 7.76 (d, J=8.0 Hz, 2H), 7.62 (d, J=8.0 Hz, 2H), 7.36-7.30 (m, 2H), 7.22 (d, J=1.6 Hz, 1H), 5.33-5.30 (m, 1H), 4.72-4.65 (m, 3H), 4.46-4.41 (m, 1H), 3.57-3.47 (m, 4H), 3.04-2.97 (m, 4H). MS: (ES, m/z): 466 [M+H]⁺.

Example 8 Preparation of (S)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(p-tolyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide

Step-1: Methyl (S)-3-bromo-4-(((2-hydroxy-1-(p-tolyl)ethyl)amino)methyl)benzoate

(S)-2-Amino-2-(p-tolyl)ethanol (209 mg, 1.380 mmol, 1 equiv), K₂CO₃ (572 mg, 4.14 mmol, 3 equiv), and MeCN (15 mL) were added to a 40-mL vial equipped with a stir bar and the resulting slurry was cooled to 0° C. in an ice-water bath. A solution of methyl 3-bromo-4-(bromomethyl)benzoate (425 mg, 1.380 mmol, 1 equiv) in MeCN (3 mL) was then added dropwise over 10 min while maintaining the internal temperature at 0° C. The ice bath was removed and the resulting slurry was allowed to slowly warm to room temperature. Stirring was continued at room temperature for 16 h and the reaction was concentrated under reduced pressure to remove most of the MeCN. The concentrated mixture was partitioned between EtOAc (10 mL) and H₂O (5 mL). The phases were separated and the organic phase was washed with brine (5 mL), dried over Na₂SO₄, filtered, and concentrated to afford the title compound as a pale yellow oil (522 mg). MS: (ES, m/z): 379 [M+H]⁺.

Step-2: Methyl (S)-3-(p-tolyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate

Methyl (S)-3-bromo-4-(((2-hydroxy-1-(p-tolyl)ethyl)amino)methyl)benzoate (522 mg, 1.380 mmol, 1 equiv) in isopropanol (8 mL) and K₂CO₃ (381 mg, 2.76 mmol, 2 equiv) were added to a 40-mL vial equipped with a stir bar followed by CuI (52.6 mg, 0.276 mmol, 0.2 equiv). The resulting solution was heated to reflux for 18 h. The reaction mixture was filtered through a celite pad and washed with isopropanol (10 mL). The filtrate was reduced in volume to ˜5 mL and 10N HCl (1.1 equiv) was added dropwise, with stirring, to the filtrate. The resulting slurry was cooled in an ice bath for 30 min before being filtered on a Buchner funnel to afford the HCl salt of the title compound as a pale yellow solid (140.4 mg, 30.5% yield). MS: (ES, m/z): 298 [M+H]⁺.

Step-3: Methyl (S)-4-(morpholine-4-carbonyl)-3-(p-tolyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate

Methyl (S)-3-(p-tolyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate hydrochloride (20 mg, 0.06 mmol, 1 equiv), Et₃N (0.029 mL, 0.21 mmol, 3.5 equiv), morpholine-4-carbonyl chloride (10.75 mg, 0.072 mmol, 1.2 equiv), and MeCN (2 mL) were added to a 4-mL vial equipped with a stir bar and the resulting solution was stirred at room temperature for 4 h. The reaction was concentrated to dryness to afford the title compound as a colorless oil (27.2 mg). MS: (ES, m/z): 411 [M+H]⁺.

Step-4: (S)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(p-tolyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide

Methyl (S)-4-(morpholine-4-carbonyl)-3-(p-tolyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate (27.2 mg, 0.066 mmol, 1 equiv), NH₂OH (50% in water, 0.087 mL, 1.32 mmol, 20 equiv), and aq. 1N NaOH (0.13 mL, 2 equiv) in a solution of THF/MeOH (4:1, 1.5 mL) were added to a 4-mL vial and the resulting solution was stirred at room temperature overnight. The reaction was concentrated to dryness and purified by prep-HPLC (Column: Xbridge Prep C18 OBD, 5 μm, 19×50 mm; Mobile Phase A: Water/0.1% formic acid; Mobile Phase B: MeCN/0.1% formic acid; Flow rate: 23 mL/min; Gradient: 0% B up to 35% B in 8 min; Detector: UV 254, 220 nm) to afford the title compound as a white solid (10.3 mg, 37.8% yield). MS: (ES, m/z): 412 [M+H]⁺.

Example 9 Preparation of (S)-3-(4-chlorophenyl)-N-hydroxy-4-(morpholine-4-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide

Step-1: Methyl (S)-3-bromo-4-(((1-(4-chlorophenyl)-2-hydroxyethyl)amino)methyl)benzoate

(S)-2-Amino-2-(4-chlorophenyl)ethan-1-ol (237 mg, 1.38 mmol, 1 equiv), K₂CO₃ (572 mg, 4.14 mmol, 3 equiv), and MeCN (15 mL) were added to a 40-mL vial equipped with a stir bar and the resulting slurry was cooled to 0° C. in an ice-water bath. A solution of methyl 3-bromo-4-(bromomethyl)benzoate (425 mg, 1.38 mmol, 1 equiv) in MeCN (3 mL) was then added dropwise over 10 min while maintaining the internal temperature at 0° C. The ice bath was removed and the resulting slurry was allowed to slowly warm to room temperature. Stirring was continued at room temperature for 16 h and the reaction was concentrated under reduced pressure to remove most of the MeCN. The concentrated mixture was partitioned between EtOAc (10 mL) and H₂O (5 mL). The phases were separated and the organic phase was washed with brine (5 mL), dried over Na₂SO₄, filtered, and concentrated to afford the title compound as a pale yellow oil (572 mg). MS: (ES, m/z): 399 [M+H]⁺.

Step-2: Methyl (S)-3-(4-chlorophenyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate

Methyl (S)-3-bromo-4-(((1-(4-chlorophenyl)-2-hydroxyethyl)amino)methyl)benzoate (572 mg, 1.435 mmol, 1 equiv) in isopropanol (5 mL) and K₂CO₃ (397 mg, 2.87 mmol, 2 equiv) were added to a 40-mL vial equipped with a stir bar followed by CuI (54.6 mg, 0.287 mmol, 0.2 equiv). The resulting solution was heated to reflux for 18 h and a second portion of K₂CO₃ (397 mg, 2.87 mmol, 2 equiv) was then added followed by the addition of another portion of copper (I) iodide (54.6 mg, 0.287 mmol, 0.2 equiv). The reaction mixture was heated to reflux for 18 h.

The resulting mixture was filtered through a celite pad and washed with isopropanol (10 mL).

The filtrate was reduced in volume to ˜5 mL and 10N HCl (1.1 equiv) was added dropwise, with stirring, to the filtrate. The resulting slurry was cooled in an ice bath for 30 min before being filtered on a Buchner funnel to afford the HCl of the title compound as a pale yellow solid (110 mg, 21.7% yield). MS: (ES, m/z): 318 [M+H]⁺.

Step-3: Methyl (S)-3-(4-chlorophenyl)-4-(morpholine-4-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate

Methyl (S)-3-(4-chlorophenyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate hydrochloride (20 mg, 0.056 mmol, 1 equiv), Et₃N (0.024 mL, 0.169 mmol, 3 equiv), morpholine-4-carbonyl chloride (9.29 mg, 0.062 mmol, 1.1 equiv), and MeCN (2 mL) were added to a 4-mL vial equipped with a stir bar and the resulting solution was stirred at room temperature for 4 h. The reaction was concentrated to dryness to afford the title compound as a colorless oil. MS: (ES, m/z): 431 [M+H]⁺.

Step-4: (S)-3-(4-Chlorophenyl)-N-hydroxy-4-(morpholine-4-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide

Methyl (S)-3-(4-chlorophenyl)-4-(morpholine-4-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate (24.13 mg, 0.056 mmol, 1 equiv), NH₂OH (50% in water, 0.074 mL, 1.12 mmol, 20 equiv), and aq. 1N NaOH (0.11 mL, 2 equiv) in a solution of THF/MeOH (4:1, 1.5 mL) were added to a 4-mL vial and the resulting solution was stirred at room temperature overnight. The reaction mixture was concentrated to dryness and purified by prep-HPLC (Column: Xbridge Prep C18 OBD, 5 μm, 19×50 mm; Mobile Phase A: Water/0.1% formic acid; Mobile Phase B: MeCN/0.1% formic acid; Flow rate: 23 mL/min; Gradient: 0% B up to 35% B in 8 min; Detector: UV 254, 220 nm) to afford the title compound as a white solid (3.2 mg, 13.2% yield). MS: (ES, m/z): 432 [M+H]⁺.

Example 10 Preparation of (S)-3-(3-chlorophenyl)-N-hydroxy-4-(morpholine-4-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide

Step-1: Methyl (S)-3-bromo-4-(((1-(3-chlorophenyl)-2-hydroxyethyl)amino)methyl)benzoate

(S)-2-Amino-2-(3-chlorophenyl)ethan-1-ol (250 mg, 1.20 mmol, 1 equiv), K₂CO₃ (664 mg, 4.81 mmol, 4 equiv), and MeCN (15 mL) were added to a 40-mL vial equipped with a stir bar and the resulting slurry was cooled to 0° C. in an ice-water bath. A solution of methyl 3-bromo-4-(bromomethyl)benzoate (370 mg, 1.20 mmol, 1 equiv) in MeCN (3 mL) was added dropwise over 10 min while maintaining the internal temperature at 0° C. The ice bath was removed and the resulting slurry was allowed to slowly warm to room temperature. Stirring was continued at room temperature for 16 h. The reaction was concentrated under reduced pressure to remove most of the MeCN and the concentrated mixture was partitioned between EtOAc (10 mL) and H₂O (5 mL). The combined organic phases were separated and washed with brine (5 mL), dried over Na₂SO₄, filtered, and concentrated to afford the title compound as a pale yellow oil (436 mg). MS: (ES, m/z): 399 [M+H]⁺.

Step-2: Methyl (S)-3-(3-chlorophenyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate

Methyl (S)-3-bromo-4-(((1-(3-chlorophenyl)-2-hydroxyethyl)amino)methyl)benzoate (436 mg, 1.09 mmol, 1 equiv) in isopropanol (5 mL) and K₂CO₃ (302 mg, 2.19 mmol, 2 equiv) were added to a 40-mL vial equipped with a stir bar followed by CuI (41.7 mg, 0.219 mmol, 0.2 equiv). The resulting solution was heated to reflux for 18 h. The resulting mixture was filtered through a celite pad and washed with isopropanol (10 mL). The filtrate was reduced in volume to ˜5 mL and 10N HCl (1.1 equiv) was added dropwise, with stirring, to the filtrate. The resulting slurry was cooled in an ice bath for 30 min before being filtered on a Buchner funnel to afford the HCl salt of the title compound as a pale yellow solid (75.6 mg, 19.5% yield). MS: (ES, m/z): 318 [M+H]⁺.

Step-3: Methyl (S)-3-(3-chlorophenyl)-4-(morpholine-4-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate

Methyl (S)-3-(3-chlorophenyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate hydrochloride (22 mg, 0.062 mmol, 1 equiv), Et₃N (0.026 mL, 0.186 mmol, 3 equiv), morpholine-4-carbonyl chloride (10.22 mg, 0.068 mmol, 1.1 equiv), and MeCN (2 mL) were added to a 4-mL vial equipped with a stir bar and the resulting solution was stirred for 16 h at 50° C. The reaction was concentrated to dryness to afford the title compound as a pale yellow oil. MS: (ES, m/z): 431 [M+H]⁺.

Step-4: (S)-3-(3-Chlorophenyl)-N-hydroxy-4-(morpholine-4-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide

Methyl (S)-3-(3-chlorophenyl)-4-(morpholine-4-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate (26.7 mg, 0.062 mmol, 1 equiv), NH₂OH (50% in water, 0.082 mL, 1.24 mmol, 20 equiv), and aq. 1N NaOH (0.12 mL, 2 equiv) in a solution of THF/MeOH (4:1, 1.5 mL) were added to a 4-mL vial and the resulting solution was stirred at room temperature overnight. The reaction was concentrated to dryness and purified directly by prep-HPLC (Column: Xbridge Prep C18 OBD, 5 μm, 19×50 mm; Mobile Phase A: Water/0.1% formic acid; Mobile Phase B: MeCN/0.1% formic acid; Flow rate: 23 mL/min; Gradient: 15% B up to 65% B in 8 min; Detector: UV 254, 220 nm) to afford the title compound as a white solid (7.7 mg, 29% yield). ¹H-NMR (300 MHz, CDCl₃) δ (ppm): 8.01 (s, 1H), 7.14-7.44 (m, 7H), 5.23 (br s, 1H), 4.96-5.42 (m, 1H), 4.23-4.72 (m, 3H), 3.63 (br s, 3H), 3.19 (br s, 4H), 1.17-1.46 (m, 2H). MS: (ES, m/z): 432 [M+H]⁺.

Example 11 Preparation of (S)-3-(4-fluorophenyl)-N-hydroxy-4-(morpholine-4-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide

Step-1: Methyl (S)-3-bromo-4-(((1-(4-fluorophenyl)-2-hydroxyethyl)amino)methyl)benzoate

(S)-2-Amino-2-(4-fluorophenyl)ethan-1-ol (260 mg, 1.68 mmol, 1 equiv), K₂CO₃ (572 mg, 4.14 mmol, 3 equiv), and MeCN (15 mL) were added to a 40-mL vial equipped with a stir bar and the resulting slurry was cooled to 0° C. in an ice-water bath. A solution of methyl 3-bromo-4-(bromomethyl)benzoate (425 mg, 1.38 mmol, 1 equiv) in MeCN (3 mL) was then added dropwise over 10 min while maintaining the internal temperature at 0° C. The ice bath was removed and the resulting slurry was allowed to slowly warm to room temperature. Stirring was continued at room temperature for 16 h. The reaction mixture was concentrated under reduced pressure to remove most of the MeCN and the concentrated mixture was partitioned between EtOAc (10 mL) and H₂O (5 mL). The phases were separated and the organic phase was washed with brine (5 mL), dried over Na₂SO₄, filtered, and concentrated to afford the title compound as a pale yellow oil (592 mg). MS: (ES, m/z): 383 [M+H]⁺.

Step-2: Methyl (S)-3-(4-fluorophenyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate

Methyl (S)-3-bromo-4-(((1-(4-fluorophenyl)-2-hydroxyethyl)amino)methyl)benzoate (592 mg, 1.55 mmol, 1 equiv) in isopropanol (5 mL) and K₂CO₃ (642 mg, 4.65 mmol, 2 equiv) were added to a 40-mL vial equipped with a stir bar followed by CuI (59 mg, 0.31 mmol, 0.2 equiv). The resulting solution was heated to reflux for 18 h. The reaction mixture was then filtered through a celite pad and washed with isopropanol (10 mL). The filtrate was reduced in volume to ˜5 mL and 10N HCl (1.1 equiv) was added dropwise, with stirring, to the filtrate. The resulting slurry was cooled in an ice bath for 30 min before being filtered on a Buchner funnel to afford the HCl salt of the title compound as a pale yellow solid (119.6 mg, 22.9% yield). MS: (ES, m/z): 302 [M+H]⁺.

Step-3: Methyl (S)-3-(4-fluorophenyl)-4-(morpholine-4-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate

Methyl (S)-3-(4-fluorophenyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate hydrochloride (60 mg, 0.178 mmol, 1 equiv), Et₃N (0.087 mL, 0.622 mmol, 3.5 equiv), morpholine-4-carbonyl chloride (0.025 mL, 0.213 mmol, 1.2 equiv), and CH₂Cl₂ (2 mL) were added to a 4-mL vial equipped with a stir bar and the resulting solution was stirred at room temperature for 16 h. The reaction mixture was then washed with aq. 1N NaOH (1 mL). The organic layer was separated, dried over Na₂SO₄, filtered, and concentrated to dryness to afford the title compound (131 mg). MS: (ES, m/z): 415 [M+H]⁺.

Step-4: (S)-3-(4-Fluorophenyl)-N-hydroxy-4-(morpholine-4-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide

Methyl (S)-3-(4-fluorophenyl)-4-(morpholine-4-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate (131 mg, 0.316 mmol, 1 equiv), NH₂OH (50% in water, 0.418 mL, 6.32 mmol, 20 equiv), and aq. 1N NaOH (0.63 mL, 2 equiv) in a solution of THF/MeOH (4:1, 1.5 mL) were added to a 4-mL vial and the resulting solution was stirred at room temperature overnight. The reaction mixture was then concentrated to dryness and purified directly by prep-HPLC (Column: Xbridge Prep C18 OBD, 5 μm, 19×50 mm; Mobile Phase A: Water/0.1% formic acid; Mobile Phase B: MeCN/0.1% formic acid; Flow rate: 23 mL/min; Gradient: 0% B up to 35% B in 8 min; Detector: UV 254, 220 nm) to afford the title compound (58.4 mg, 44.5% yield). ¹H-NMR (300 MHz, CDCl₃) δ (ppm): 8.10 (br d, J=16.7 Hz, 1H), 7.18-7.40 (m, 4H), 6.85-7.18 (m, 3H), 5.19 (br s, 2H), 4.37-4.71 (m, 3H), 4.28 (br s, 2H), 3.65-4.01 (m, 1H), 3.58 (br s, 3H), 3.27-3.52 (m, 5H), 3.14 (br s, 4H), 2.78 (br s, 1H), 1.25 (br s, 1H). MS: (ES, m/z): 416 [M+H]⁺.

Example 12 Preparation of (R)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(pyridin-3-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide and (S)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(pyridin-3-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide

Step-1: Methyl 3-bromo-4-(((2-hydroxy-1-(pyridin-3-yl)ethyl)amino)methyl)benzoate

A solution of 2-amino-2-(pyridin-3-yl)ethan-1-ol dihydrochloride (980 mg, 4.64 mmol, 2 equiv) in MeCN (40 mL) was added to a 250-mL round-bottom flask followed by the portionwise addition of K₂CO₃ (1.29 g, 9.33 mmol, 4 equiv). To this mixture was added a solution of methyl 3-bromo-4-(bromomethyl)benzoate (713 mg, 2.32 mmol, 1 equiv) in MeCN (20 mL) dropwise and with stirring. The resulting solution was stirred overnight at room temperature and then concentrated under vacuum. The residue was dissolved in 40 mL of water and extracted with EtOAc (3×60 mL). The combined organic layers were dried over anhydrous Na₂SO₄, filtered, and concentrated under vacuum. The residue was purified by silica gel chromatography (MeOH/CH₂Cl₂, 1:20) to afford the title compound as a light brown solid (380 mg, 43% yield). MS: (ES, m/z): 365 [M+H]⁺.

Step-2: Methyl 3-(pyridin-3-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate

A solution of methyl 3-bromo-4-((2-hydroxy-1-(pyridin-3-yl)ethylamino)methyl) benzoate (260 mg, 0.71 mmol, 1 equiv) in isopropanol (8 mL) was added to a 10-mL sealed tube purged and maintained with an inert atmosphere of nitrogen followed by the portionwise addition of K₂CO₃ (147.5 mg, 1.07 mmol, 1.5 equiv). To this mixture was added CuI (67.6 mg, 0.35 mmol, 0.5 equiv) in portions and the resulting solution was stirred overnight at 105° C. in an oil bath. The reaction mixture was cooled to room temperature with a water/ice bath and then concentrated under vacuum. The residue was dissolved in EtOAc (80 mL) and washed with brine (3×30 mL), The combined organic layers were dried over anhydrous Na₂SO₄, filtered, and concentrated under vacuum to afford the title compound as light yellow oil (210 mg) which was used to the next step without purification. MS: (ES, m/z): 285 [M+H]⁺.

Step-3: Methyl (R)-4-(morpholine-4-carbonyl)-3-(pyridin-3-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate and Methyl (S)-4-(morpholine-4-carbonyl)-3-(pyridin-3-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate

Methyl 3-(pyridin-3-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxylate (100 mg, 0.35 mmol, 1 equiv) in CH₂Cl₂ (2.5 mL) were added to an 8-mL vial followed by the addition of Et₃N (177.8 mg, 1.76 mmol, 5 equiv) and triphosgene (52.1 mg, 0.18 mmol, 0.5 equiv) at 0° C. The mixture was stirred for 30 min at room temperature and morpholine (61.2 mg, 0.70 mmol, 2 equiv) was then added. The resulting solution was stirred for 2 h at room temperature and then concentrated under vacuum. The crude product was purified by flash-prep-HPLC (Column: C18, 40 g, 20-45 μm, 100 Å; Mobile Phase A: Water/0.05% TFA; Mobile Phase B: MeCN; Flow rate: 80 mL/min; Gradient: 5% B to 30% B in 30 min; Detector: UV 254, 220 nm). The pH value of the collected fractions was then adjusted to 8 with aq. 1N NaOH solution. The resulting solution was extracted with CH₂Cl₂ (2×150 mL). The combined organic layers were dried over anhydrous Na₂SO₄, filtered, and concentrated under vacuum to afford the racemate of the title compounds as a white solid (40 mg, 29%). The racemate was separated by chiral prep-HPLC (Column: Phenomenex Lux Cellulose-4, AXIA Packed, 5 μm, 21.2×250 mm; Mobile Phase: MeOH; Flow rate: 20 mL/min; Detector: UV 254, 220 nm) to afford the single isomers of the title compounds as white solids. First eluting isomer, arbitrarily drawn as the R isomer: (15 mg, 38% yield); second eluting isomer, arbitrarily drawn as the S isomer: (18 mg, 45% yield). MS: (ES, m/z): 398 [M+H]⁺.

Step-4: (R)—N-Hydroxy-4-(morpholine-4-carbonyl)-3-(pyridin-3-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide and (S)—N-Hydroxy-4-(morpholine-4-carbonyl)-3-(pyridin-3-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide

Into 8-mL vials was added each of the separated isomers from Step 3 (15 mg, 0.04 mmol; and 18 mg, 0.05 mmol; 1 equiv) in THF/MeOH (4:1, 2.5 mL), followed by aq. 1N NaOH (2 equiv) and NH₂OH (50% in H₂O, 60 equiv). The resulting solution was stirred for 3 h at room temperature and the crude products were purified by prep-HPLC (Column: Xbridge C18 OBD, 5 μm, 19×250 mm; Mobile Phase A: Water/10 mM NH₄HCO₃; Mobile Phase B: MeCN; Gradient: 3% B to 30% B in 8 min; Detector: UV 254, 220 nm) to afford the title compounds as white solids. Product from the reaction with the first eluting isomer of Step 3: (6.1 mg, 41% yield); ¹H-NMR (400 MHz, DMSO-d₆) δ (ppm): 11.13 (br s, 1H), 9.01 (br s, 1H), 8.62 (s, 1H), 8.49 (d, J=4.4 Hz, 1H), 7.80 (d, J=8.0 Hz, 1H), 7.42-7.36 (m, 2H), 7.34-7.24 (m, 2H), 5.27-5.26 (m, 1H), 4.70-4.61 (m, 3H), 4.51-4.48 (m, 1H), 3.56-3.51 (m, 4H), 3.02-3.01 (m, 4H). Product from the reaction with the second eluting isomer of Step 3: (7.6 mg, 42% yield); ¹H-NMR (400 MHz, DMSO-d₆) δ (ppm): 9.01 (br s, 1H), 8.62 (s, 1H), 8.50 (d, J=3.6 Hz, 1H), 7.80 (d, J=7.6 Hz, 1H), 7.42-7.36 (m, 2H), 7.34-7.24 (m, 2H), 5.26-5.25 (m, 1H), 4.70-4.61 (m, 3H), 4.51-4.77 (m, 1H), 3.56-3.48 (m, 4H), 3.02-3.00 (m, 4H). MS: (ES, m/z): 399 [M+H]+:

Example 13 In Vitro Histone Deacetylase Assay

The enzymatic HDAC6 assay was performed using electrophoretic mobility shift assay. Full length human recombinant HDAC6 protein was expressed in baculoviral system and purified by affinity chromatography. The enzymatic reactions were assembled in 384 well plates and in a total volume of 25 μL in a reaction buffer comprising: 100 mM HEPES, pH 7.5, 25 mM KCl, 0.1% bovine serum albumin, 0.01% Triton X-100, 1% DMSO (from compounds), 2 M of the fluorescently labeled peptide substrate, and enzyme. The enzyme was added at a final concentration of 1 nM and the peptide substrate RHKK(Ac)—NH2 was used. The compounds were tested at 12 concentrations spaced by 3× dilution intervals. Negative control samples (0%-inhibition in the absence of inhibitor) and positive control samples (100%-inhibition) were assembled in replicates of four in each assay plate. The reactions were incubated at 25° C. and quenched by the addition of 45 μL of termination buffer (100 mM HEPES, pH 7.5, 0.01% Triton X-100, 0.05% SDS).

The terminated assay plates were analyzed on LabChip® 3000 microfluidic electrophoresis instrument (Perkin Elmer/Caliper Life Sciences). The fluorescence intensity of the electrophoretically separated de-acetylated product and substrate peptide was measured.

Activity in each sample was determined as the product to sum ratio (PSR): P/(S+P), where P is the peak height of the product peptide and S is the peak height of the substrate peptide. Percent inhibition (P_(inh)) is determined using the following equation:

P_(inh)=(PSR_(0%)−PSR_(inh))/(PSR_(0%)−PSR_(100%))*100, where PSR_(inh) is the product sum ratio in the presence of inhibitor, PSR_(0%) is the average product sum ration in the absence of inhibitor, and PSR_(100%) is the average product sum ratio in 100%-inhibition control samples. The IC₅₀ values of inhibitors were determined by fitting the %-inhibition curves with 4 parameter dose-response model using XLfit 4 software.

As set forth in Table 4, below, IC₅₀ values are defined as follows: IC50≦0.1 μM (+++); IC50>0.1 μM and ≦0.5 μM (++); IC50>0.5 μM (+).

TABLE 4 Inhibitory Concentration (IC₅₀) Values for Representative Compounds against HDAC6. Activity COMPOUND NAME Range (R)-N-hydroxy-4-methyl-3-phenyl-2,3,4,5- +++ tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide (R)-N-hydroxy-4-(4-methoxybenzyl)-3-phenyl-2,3,4,5- +++ tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide (R)-N-hydroxy-3,4-diphenyl-2,3,4,5- ++ tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide (S)-N-hydroxy-4-methyl-3-phenyl-2,3,4,5- +++ tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide (S)-N-hydroxy-4-(4-methoxybenzyl)-3-phenyl-2,3,4,5- +++ tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide (S)-N-hydroxy-3,4-diphenyl-2,3,4,5- +++ tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide (S)-4-((4-fluorophenyl)sulfonyl)-N-hydroxy-3-phenyl-2,3,4,5- ++ tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide (S)-N8-hydroxy-N4,N4-dimethyl-3-phenyl-2,3- +++ dihydrobenzo[f][1,4]oxazepine-4,8(5H)-dicarboxamide (S)-N-hydroxy-4-(morpholine-4-carbonyl)-3-phenyl-2,3,4,5- +++ tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide (S)-N-hydroxy-4-(4-methoxypiperidine-1-carbonyl)-3-phenyl- +++ 2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide (S)-N-hydroxy-4-(4-methylpiperazine-1-carbonyl)-3-phenyl- +++ 2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide (S)-4-(4-acetylpiperazine-1-carbonyl)-N-hydroxy-3-phenyl- +++ 2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide (S)-N-hydroxy-4-(morpholine-4-carbonyl)-3-(4- +++ (trifluoromethyl)phenyl)-2,3,4,5- tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide (S)-N-hydroxy-3-phenyl-4-(piperidine-1-carbonyl)-2,3,4,5- +++ tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide (S)-N-hydroxy-3-phenyl-4-(pyrrolidine-1-carbonyl)-2,3,4,5- +++ tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide (S)-N4-cyclohexyl-N8-hydroxy-3-phenyl-2,3- +++ dihydrobenzo[f][1,4]oxazepine-4,8(5H)-dicarboxamide (S)-N8-hydroxy-3-phenyl-N4-(tetrahydro-2H-pyran-4-yl)-2,3- +++ dihydrobenzo[f][1,4]oxazepine-4,8(5H)-dicarboxamide (S)-N8-hydroxy-N4,3-diphenyl-2,3- +++ dihydrobenzo[f][1,4]oxazepine-4,8(5H)-dicarboxamide (S)-N8-hydroxy-3-phenyl-N4-(pyridin-4-yl)-2,3- +++ dihydrobenzo[f][1,4]oxazepine-4,8(5H)-dicarboxamide (S)-N8-hydroxy-3-phenyl-N4-(pyridin-3-yl)-2,3- +++ dihydrobenzo[f][1,4]oxazepine-4,8(5H)-dicarboxamide (S)-N-hydroxy-4-(morpholine-4-carbonyl)-3-(p-tolyl)-2,3,4,5- +++ tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide (S)-3-(4-chlorophenyl)-N-hydroxy-4-(morpholine-4-carbonyl)- +++ 2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide (S)-3-(3-chlorophenyl)-N-hydroxy-4-(morpholine-4-carbonyl)- +++ 2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide (R)-N-hydroxy-4-(morpholine-4-carbonyl)-3-(pyridin-3-yl)- + 2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide (S)-N-hydroxy-4-(morpholine-4-carbonyl)-3-(pyridin-3-yl)- +++ 2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide (S)-3-(4-fluorophenyl)-N-hydroxy-4-(morpholine-4-carbonyl)- +++ 2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide

EQUIVALENTS

While the present invention has been described in conjunction with the specific embodiments set forth above, many alternatives, modifications and other variations thereof will be apparent to those of ordinary skill in the art. All such alternatives, modifications and variations are intended to fall within the spirit and scope of the present invention. 

1. A compound of Formula I:

or a pharmaceutically acceptable salt, prodrug, solvate, hydrate, tautomer or isomer thereof, wherein: X¹ is independently CR¹R², NR³, O, or C═O; X² and X⁴ are each independently CR¹R², C═O, S(O) or SO₂; X³ is CR^(1′)R^(2′); wherein X⁴, X², and X¹ are not all simultaneously CR¹R²; Y¹ and Y⁴ are not bonded to —C(O)NHOH and are each independently N or CR¹; Y² and Y³ are each independently N or CR¹ when not bonded to —C(O)NHOH and Y² and Y³ are C when bonded to —C(O)NHOH; L is a bond, —(CR¹R²)_(n)—, —C(O)O—, —C(O)NR³—, —S(O)₂—, —S(O)₂NR³—, —S(O)—, or —S(O)NR³—, wherein L is bound to the ring nitrogen through the carbonyl or sulfonyl group; R is independently —H, —C₁-C₆ alkyl, —C₂-C₆ alkenyl, —C₄-C₈ cycloalkenyl, —C₂-C₆ alkynyl, —C₃-C₈ cycloalkyl, —C₅-C₁₂ spirocycle, heterocyclyl, spiroheterocyclyl, aryl, or heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O, wherein each alkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkyl, spirocycle, heterocyclyl, spiroheterocyclyl, aryl, or heteroaryl is optionally substituted with one or more —OH, halogen, oxo, —NO₂, —CN, —R¹, —R², —OR³, —NHR³, —NR³R⁴, —S(O)₂NR³R⁴, —S(O)₂R¹, —C(O)R¹, —CO₂R¹, —NR³S(O)₂R¹, —S(O)R¹, —S(O)NR³R⁴, —NR³S(O)R¹, heterocycle, aryl, or heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O; each R¹ and R² are independently, and at each occurrence, —H, —R³, —R⁴, —C₁-C₆ alkyl, —C₂-C₆ alkenyl, —C₄-C₈ cycloalkenyl, —C₂-C₆ alkynyl, —C₃-C₈ cycloalkyl, heterocyclyl, aryl, heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O, —OH, halogen, —NO₂, —CN, —NHC₁-C₆ alkyl, —N(C₁-C₆ alkyl)₂, —S(O)₂N(C₁-C₆ alkyl)₂, —N(C₁-C₆ alkyl)S(O)₂R⁵, —S(O)₂(C₁-C₆ alkyl), —(C₁-C₆ alkyl)S(O)₂R⁵, —C(O)C₁-C₆ alkyl, —CO₂C₁-C₆ alkyl, —N(C₁-C₆ alkyl)S(O)₂C₁-C₆ alkyl, or —(CHR⁵)_(n)NR³R⁴, wherein each alkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, or heteroaryl is optionally substituted with one or more substituents selected from —OH, halogen, —NO₂, oxo, —CN, —R⁵, —OR³, —NHR³, NR³R⁴, —S(O)₂N(R³)₂—, —S(O)₂R⁵, —C(O)R⁵, —CO₂R⁵, —NR³S(O)₂R⁵, —S(O)R⁵, —S(O)NR³R⁴, —NR³S(O)R⁵, heterocycle, aryl, and heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O; or R¹ and R² can combine with the atom to which they are both attached to form a spirocycle, spiroheterocycle, or a spirocycloalkenyl; or R¹ and R², when on adjacent atoms, can combine to form a heterocycle, cycloalkyl, aryl, heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O, or cycloalkenyl; or R¹ and R², when on non-adjacent atoms, can combine to form a bridging cycloalkyl, cycloalkenyl, or heterocycloalkyl; R^(1′) and R^(2′) are independently, and at each occurrence, H, aryl, or heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O, wherein each aryl or heteroaryl is optionally substituted with one or more substituents selected from —OH, halogen, —NO₂, oxo, —CN, —R³, —R⁵, —OR³, —NHR³, —NR³R⁴, —S(O)₂N(R³)₂, —S(O)₂R⁵, —C(O)R⁵, —CO₂R⁵, —NR³S(O)₂R⁵, —S(O)R⁵, —S(O)NR³R⁴, —NR³S(O)R⁵, heterocycle, aryl, and heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O, wherein at least one of R^(1′) or R^(2′) is not H; R³ and R⁴ are independently, and at each occurrence, —H, —C₁-C₆ alkyl, —C₂-C₆ alkenyl, —C₄-C₈ cycloalkenyl, —C₂-C₆ alkynyl, —C₃-C₈ cycloalkyl, heterocyclyl, aryl, heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O, —S(O)₂N(C₁-C₆ alkyl)₂, —S(O)₂(C₁-C₆ alkyl), —(C₁-C₆ alkyl)S(O)₂R⁵, —C(O)C₁-C₆ alkyl, —CO₂C₁-C₆ alkyl, or —(CHR⁵)_(n)N(C₁-C₆ alkyl)₂, wherein each alkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, or heteroaryl is optionally substituted with one or more substituents selected from —OH, halogen, —NO₂, oxo, —CN, —R⁵, —O(C₁-C₆) alkyl, —NH(C₁-C₆) alkyl, —N(C₁-C₆ alkyl)₂, —S(O)₂N(C₁-C₆ alkyl)₂, —S(O)₂NHC₁-C₆ alkyl, —C(O)C₁-C₆ alkyl, —CO₂C₁-C₆ alkyl, —N(C₁-C₆ alkyl)S(O)₂C₁-C₆ alkyl, —S(O)R⁵, —S(O)N(C₁-C₆ alkyl)₂, —N(C₁-C₆ alkyl)S(O)R⁵, heterocycle, aryl, and heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O; or R³ and R can combine with the nitrogen atom to which they are attached to form a heterocycle or heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O, wherein each heterocycle or heteroaryl is optionally substituted with —R⁴, —OR⁴, or —NR⁴R⁵; R⁵ is independently, and at each occurrence, —H, —C₁-C₆ alkyl, —C₂-C₆ alkenyl, —C₄-C₈ cycloalkenyl, —C₂-C₆ alkynyl, —C₃-C₈ cycloalkyl, heterocyclyl, aryl, heteroaryl containing 1 to 5 heteroatoms selected from the group consisting of N, S, P, and O, —OH, halogen, —NO₂, —CN, —NHC₁-C₆ alkyl, —N(C₁-C₆ alkyl)₂, —S(O)₂NH(C₁-C₆ alkyl), —S(O)₂N(C₁-C₆ alkyl)₂, —S(O)₂C₁-C₆ alkyl, —C(O)C₁-C₆ alkyl, —CO₂C₁-C₆ alkyl, —N(C₁-C₆ alkyl)SO₂C₁-C₆ alkyl, —S(O)(C₁-C₆ alkyl), —S(O)N(C₁-C₆ alkyl)₂, —N(C₁-C₆ alkyl)S(O)(C₁-C₆ alkyl) or —(CH₂)_(n)N(C₁-C₆ alkyl)₂; and each n is independently and at each occurrence an integer from 0 to 6; and provided that when X² and X⁴ are both C═O, X¹ is not NR³.
 2. The compound of claim 1, wherein X⁴ is CR¹R².
 3. The compound of claim 1, wherein the compound is of the Formula IA:

or a pharmaceutically acceptable salt, prodrug, solvate, hydrate, tautomer or stereoisomer thereof.
 4. The compound of claim 3, wherein X⁴ is CR¹R².
 5. The compound of claim 3, wherein X¹ is NR³, O, or C═O.
 6. The compound of claim 3, wherein X¹ is O.
 7. The compound of claim 3, wherein X¹ is O and X⁴ is CR¹R².
 8. The compound of claim 3, wherein the compound is of the Formula IA-1:


9. The compound of claim 8, wherein the compound is of the Formula IA-1a, Formula IA-1b, or Formula IA-1c:


10. The compound of claim 3, wherein the compound is of the Formula IA-2:


11. The compound of claim 3, wherein the compound is of the Formula IA-3:


12. The compound of claim 3, wherein the compound is of the Formula IA-4:


13. The compound of claim 3, wherein the compound is of the Formula IA-5:


14. The compound of claim 3, wherein the compound is of the Formula IA-6:


15. The compound of claim 3, wherein the compound is of the Formula IA-7:


16. The compound of claim 3, wherein the compound is of the Formula IA-8:


17. The compound of claim 3, wherein the compound is of the Formula IA-9:


18. The compound of claim 3, wherein the compound is of the Formula IA-10:


19. The compound of claim 3, wherein the compound is of the Formula IA-11:


20. The compound of claim 1, wherein the compound is of the Formula IB

or a pharmaceutically acceptable salt, prodrug, solvate, hydrate, enantiomer or stereoisomer thereof.
 21. The compound of claim 20, wherein X⁴ is CR¹R².
 22. The compound of claim 20, wherein X¹ is NR³, O, or C═O.
 23. The compound of claim 20, wherein X¹ is O.
 24. The compound of claim 20, wherein X¹ is O and X⁴ is CR¹R².
 25. The compound of claim 20, wherein X¹ is N, X² is C═O, and X⁴ is CR¹R².
 26. The compound of claim 20, wherein the compound is of the Formula IB-1:


27. The compound of claim 20, wherein the compound is of the Formula IB-2:


28. The compound of claim 20, wherein the compound is of the Formula (IB-3):


29. The compound of claim 20, wherein the compound is of the Formula IB-4:


30. The compound of claim 20, wherein the compound is of the Formula (IB-5):


31. The compound of claim 1, selected from the group consisting of: (S)—N-hydroxy-4-methyl-3-phenyl-2,3,4,5-tetrahydrobenzo[1,4]oxazepine-8-carboxamide; (R)—N-hydroxy-4-methyl-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (S)—N-hydroxy-4-(4-methoxybenzyl)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (R)—N-hydroxy-4-(4-methoxybenzyl)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (S)—N-hydroxy-3,4-diphenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (R)—N-hydroxy-3,4-diphenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (S)—N-hydroxy-4-(4-methoxypiperidine-1-carbonyl)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (S)—N-hydroxy-4-(4-methylpiperazine-1-carbonyl)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (S)-4-(4-acetylpiperazine-1-carbonyl)-N-hydroxy-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (S)—N-hydroxy-3-phenyl-4-(piperidine-1-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (S)—N-hydroxy-3-phenyl-4-(pyrrolidine-1-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (S)—N4-cyclohexyl-N8-hydroxy-3-phenyl-2,3-dihydrobenzo[f][1,4]oxazepine-4,8(5H)-dicarboxamide; (S)—N8-hydroxy-3-phenyl-N4-(tetrahydro-2H-pyran-4-yl)-2,3-dihydrobenzo[f][1,4]oxazepine-4,8(5H)-dicarboxamide; (S)—N8-hydroxy-N4,3-diphenyl-2,3-dihydrobenzo[f][1,4]oxazepine-4,8(5H)-dicarboxamide; (S)—N8-hydroxy-3-phenyl-N4-(pyridin-4-yl)-2,3-dihydrobenzo[f][1,4]oxazepine-4,8(5H)-dicarboxamide; (S)—N8-hydroxy-3-phenyl-N4-(pyridin-3-yl)-2,3-dihydrobenzo[f][1,4]oxazepine-4,8(5H)-dicarboxamide; (S)—N-hydroxy-4-(morpholine-4-carbonyl)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (S)—N8-hydroxy-N4,N4-dimethyl-3-phenyl-2,3-dihydrobenzo[f][1,4]oxazepine-4,8(5H)-dicarboxamide; (S)-4-((4-fluorophenyl)sulfonyl)-N-hydroxy-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (S)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(4-(trifluoromethyl)phenyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (S)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(p-tolyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (S)-3-(4-chlorophenyl)-N-hydroxy-4-(morpholine-4-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (S)-3-(3-chlorophenyl)-N-hydroxy-4-(morpholine-4-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (S)-3-(4-fluorophenyl)-N-hydroxy-4-(morpholine-4-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (R)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(pyridin-3-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; and (S)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(pyridin-3-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide.
 32. The compound of claim 1, selected from the group consisting of: (S)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(o-tolyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (S)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(3-(trifluoromethyl)phenyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (R)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(3-(trifluoromethyl)phenyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (S)-3-(3-fluorophenyl)-N-hydroxy-4-(morpholine-4-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide (R)-3-(3-fluorophenyl)-N-hydroxy-4-(morpholine-4-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide (S)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(2-(trifluoromethyl)phenyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide (R)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(2-(trifluoromethyl)phenyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (S)-3-(2-fluorophenyl)-N-hydroxy-4-(morpholine-4-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (R)-3-(2-fluorophenyl)-N-hydroxy-4-(morpholine-4-carbonyl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide (S)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(quinoxalin-6-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (S)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(quinolin-6-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide (S)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(quinolin-7-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (S)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(naphthalen-2-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (R)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(quinoxalin-6-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (R)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(quinolin-6-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (R)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(quinolin-7-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (R)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(naphthalen-2-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (R)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(quinoxalin-5-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (R)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(quinolin-5-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (R)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(quinolin-8-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (R)—N-hydroxy-4-(morpholine-4-carbonyl)-3-(naphthalen-1-yl)-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; (3S)—N-hydroxy-5-methyl-4-(morpholine-4-carbonyl)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide; and (S)-6-fluoro-N-hydroxy-4-(morpholine-4-carbonyl)-3-phenyl-2,3,4,5-tetrahydrobenzo[f][1,4]oxazepine-8-carboxamide.
 33. A pharmaceutical composition comprising a compound of claim 1 and a pharmaceutically acceptable carrier.
 34. A method of treating a disease associated with HDAC6 modulation in a subject in need thereof, comprising administering to the subject an effective amount of a compound of claim
 1. 35. The method of claim 34, wherein the disease is cancer, neurodegenerative disease, neurodevelopmental disorder, inflammatory or autoimmune disease, infection, metabolic disease, hematologic disease, or cardiovascular disease.
 36. The method of claim 35, wherein the cancer is cutaneous T-cell lymphoma, peripheral T-cell lymphoma, multiple myeloma, leukemia, lung, ovarian, breast, prostate, pancreatic, hepatocellular or renal cancer.
 37. The method of claim 35, wherein the neurodegenerative disease is Alzheimer's, Huntington's, Parkinson's, Amyotrophic Lateral Sclerosis, or spinal muscular atrophy.
 38. The method of claim 35, wherein the neurodevelopmental disorder is Rett syndrome.
 39. The method of claim 35, wherein the inflammatory or autoimmune disease is rheumatoid arthritis, spondylitis arthritis, psoriatic arthritis, psoriasis, multiple sclerosis, systemic lupus erythematosus, inflammatory bowel diseases, graft versus host disease, transplant rejection or fibrotic disease.
 40. The method of claim 34, wherein the compound inhibits a histone deacetylase.
 41. The method of claim 34, wherein the compound inhibits a zinc-dependent histone deacetylase.
 42. The method of claim 34, wherein the compound inhibits the HDAC6 isozyme zinc-dependent histone deacetylase.
 43. (canceled)
 44. (canceled) 